Networking, Security & Cloud

Versa SD-WAN Command line quick reference.

2025-06-25T09:30:00.000+05:30

Section 1: Console

# To switch from Shell to cli

admins@versa-sdwan01$ cli
admins@versa-sdwan01-cli>

# To switch from Cli to shell

admins@versa-sdwan01-cli> shell OR exit
admins@versa-sdwan01$

Section 2: Getting System Details

CMD 2.1: To Get LSB release information (LSB = Linux Standard Base and Distribution information.)

admins@versa-sdwan01$lsb_release -a

CMD 2.2: To Get Serial, model and Software version.

admins@versa-sdwan01-cli> show system details

CMD 2.2 To get only Serial and model number.

admins@versa-sdwan01-cli> show device hardware

Section 3: Interface Command.

CMD 3.1: Get interface detail information.

• Physical interface (Host interface) associated with VNI
• MTU / Speed / Duplex
• Routing instance associated with Interface.

admins@versa-sdwan01-cli> show interfaces detail vni-0/0

CMD3.2.1 Get SFP information.

admins@versa-sdwan01-cli> show interfaces sfpinfo vni-0/0

CMD 3.3 Interface utilization

admins@versa-sdwan01-cli> show interfaces info Tenent-Name vni-0/0

CMD: Enable interface via cli.

versa@versa-flexvnf:~$ versa@versa-flexvnf:~$ cli versa@versa-flexvnf-cli> show interfaces detail vni-0/9

Section 4: Configuring interface, enable interface.

versa@versa-flexvnf-cli> configure
versa@versa-flexvnf-cli(config)%
versa@versa-flexvnf-cli(config)% set interfaces vni-0/9 enable

Cisco Hardware refresh model recommendations

2025-06-24T22:43:00.003+05:30

Cisco Hardware Refresh Jun 2025

Based on various Cisco website and other online resources

Acces switches

Old Device	New Device
2960X/2960XR	catalyst 9200
3650/3850	catalyst 9300
4500-E series	catalyst 9400
Desktop switch	catalyst 9200CX

Cisco catalyst 9200 switch characteristic:

• Lower total stacking bandwidth
• Lower switching and forwarding capacity than catalyst 9300
• Powered by IOS XE Lite OS
• Only ethernet connectivity no fiber
• No application hosting support

Catalyst 9300

• Provides both fixed and modular uplink option
• Application hosting support
• Fiber and copper connectivity options
• Stacking upto 8 switches with power stacking

Catalyst 9400

• Multiple supervisor modules
• Modular chassis design for access layer, available in 4 ,7 and 10 slot chassis with multiple supervisor modules
• Dual Chassi stacking (StackWise virtual)
• Application hosting support
• Great for long-term investment protection.

Core switches

Old Device	New Device
3850-XS /4500	Catalyst 9500 series
6840 -X /6880-X	Catalyst 9500 series
6500-E/6807-XL	Catalyst 9600 series

Features 9500

• 1RU
• High performance
• Core layer device
• 1gig to 400Gig port speed
• Not stackable

Features 9600

• For high-capacity environment like campus core
• Come with big ACL, MAC and route table scales and buffers
• Rely on a centralized architecture
• 25.4 Tbs switching capacity

Wireless Controller

Old Device	New Device
WLC 5820	WLC 9800

WLC 9800 WLC Feature

• Cisco Catalyst 9800 hardware or VM
• 100 Gb bw
• 250 to 6000 ap
• 5k to 64K client.

Branch WAN Router

Old Device	New Device
ISR 4221 and 4321	catalyst 8200L
ISR 4321 and 4331	8200 Series
ISR 4351, 4431, 4451	8300 Series

WAN aggregation Router

Old Device	New Device
ASR 1000	Catalyst 8500

Catalyst 8500 and 8500L series switches

• 1RU or 3RU
• Fixed configuration, no expansion model
• This router focused on high performance and bandwidth compared to 8200 and 8300

Virtual Router

Old Device	New Device
CSR 1000v, ENCS 5100 Series	Catalyst 8000V

Ubuntu

2025-06-22T22:59:00.005+05:30

Linux : Ubuntu

While installing Ubuntu you get 3 options:

1: "Install alongside" – retain existing os

2: “Erase Disk” - fresh new installation deleting existing data.

3: "Manual partitioning" – Customize partitions. – If you don’t want to delete existing data

Manual partitioning:

Create free space and click add following three partitions.

1: File System Partition : ESP (Efi System Partition)

Size: min 100Mb max 500Mb

use as VFAT

Mount point : N/A

It is a FAT formatted partition containing the primary EFI boot loader(s) for installed operating systems.

2: SWAP: use as swap

Size: 4Gb

use as Swap

Mount point : N/A

3: File systm partition used by OS

Size: Maximum (depending upon availability and requirement)

use as EXT4

Mount point : /

apt : advanced package tool

To update local package index with information from configured repositories, it downloads latest list of available packages and their versions but do not install or upgrade any packages.

Admin@Ubuntu#:~$ sudo apt-get update

To upgrade all currently installed packages on system to latest version.

Admin@Ubuntu#:~$ sudo apt-get upgrade

To check Ubuntu software version:

Admin@Ubuntu#:~$ lsb_release -a

------------- output start --------------------

No LSB modules are available.

Distributor ID: Ubuntu

Description: Ubuntu 24.04.2

LTS Release: 24.04 Codename: noble

------------- output end --------------------

Admin@Ubuntu#:~$ cat /etc/lsb-release

DISTRIB_ID=Ubuntu

DISTRIB_RELEASE=24.04

DISTRIB_CODENAME=noble

DISTRIB_DESCRIPTION="Ubuntu 24.04.2 LTS"

2024-11-10T16:14:00.001+05:30

Cisco Nexus Switch CLI Cheat Sheet

Running Several Command on Single line.

Nexus# Conf t; int eth 1/1; no switch port; no shut

Roll back config change using checkpoint.

Create Checkpoint: Nexus# checkpoint <Check-Point-Name>

Verify Checkpoint: Nexus# show checkpoint summary

Compare Config: Nexus # show diff rollback-path checkpoint <Check-Point-Name> running-config

Rollback Config: Nexus# rollback running-config checkpoing <Check-Point-Name>

Filter Command Ouput.

Nexus# show ip int brief | grep -i vlan
Nexus# show clock | ex NTP

Working with VRF

routing-context vrf <VRF-NAME>

Show ip route

routing-context vrf default

Terminal color

Nexus# terminal color

alias

Nexus(config)# cli alias name <ALIAS-NAME> <Command>

Verify accounting log

Nexus# show accounting log | last 10

Wireless Networking Cheat Sheet

2024-10-26T00:04:00.004+05:30

Wireless Networking Cheat Sheet

Wireless Standards

- 802.11a: 5 GHz, up to 54 Mbps, shorter range.
- 802.11b: 2.4 GHz, up to 11 Mbps, longer range.
- 802.11g: 2.4 GHz, up to 54 Mbps, backward compatible with 802.11b.
- 802.11n: 2.4/5 GHz, up to 600 Mbps, uses MIMO technology.
- 802.11ac: 5 GHz, up to 3.46 Gbps, wider channels and MU-MIMO.
- 802.11ax (Wi-Fi 6): 2.4/5 GHz, higher efficiency and capacity.

Common Wireless Terms

- SSID: Service Set Identifier, the name of the wireless network.
- BSSID: Basic Service Set Identifier, the MAC address of the access point.
- WPA/WPA2/WPA3: Security protocols for wireless networks.
- Channel: The frequency used for communication, often overlapping in the 2.4 GHz band.
- MIMO: Multiple Input Multiple Output, technology that uses multiple antennas to improve performance.

Wireless Security Protocols

- WEP: Wired Equivalent Privacy, outdated and insecure.
- WPA: Wi-Fi Protected Access, improved security over WEP.
- WPA2: Enhanced security, uses AES encryption.
- WPA3: Latest security protocol, offers stronger encryption and protection against brute-force attacks.

Wireless Configuration Commands (Windows)

- Show available Wi-Fi networks:
  netsh wlan show networks

- Connect to a Wi-Fi network:
  netsh wlan connect name=""

- Disconnect from a Wi-Fi network:
  netsh wlan disconnect

Wireless Troubleshooting Commands

- Ping the access point:
  ping 

- Check signal strength:
  netsh wlan show interfaces

- View wireless network properties:
  netsh wlan show profile "" key=clear

Common Wireless Issues

- Weak signal: Check distance from the access point, obstacles, and interference.
- Connection drops: Update drivers, check for interference, and signal strength.
- No internet access: Verify DHCP settings, check ISP connection, and router status.

Best Practices for Wireless Networking

- Use WPA3 for better security.
- Select less crowded channels (1, 6, 11 in 2.4 GHz).
- Position access points centrally to optimize coverage.
- Limit SSID broadcasting for sensitive networks.
- Regularly update firmware on access points and routers.

Windows Command for Network Engineer

2024-10-25T23:51:00.005+05:30

Wireless Networking Cheat Sheet

Wireless Standards

- 802.11a: 5 GHz, up to 54 Mbps, shorter range.
- 802.11b: 2.4 GHz, up to 11 Mbps, longer range.
- 802.11g: 2.4 GHz, up to 54 Mbps, backward compatible with 802.11b.
- 802.11n: 2.4/5 GHz, up to 600 Mbps, uses MIMO technology.
- 802.11ac: 5 GHz, up to 3.46 Gbps, wider channels and MU-MIMO.
- 802.11ax (Wi-Fi 6): 2.4/5 GHz, higher efficiency and capacity.

Common Wireless Terms

- SSID: Service Set Identifier, the name of the wireless network.
- BSSID: Basic Service Set Identifier, the MAC address of the access point.
- WPA/WPA2/WPA3: Security protocols for wireless networks.
- Channel: The frequency used for communication, often overlapping in the 2.4 GHz band.
- MIMO: Multiple Input Multiple Output, technology that uses multiple antennas to improve performance.

Wireless Security Protocols

- WEP: Wired Equivalent Privacy, outdated and insecure.
- WPA: Wi-Fi Protected Access, improved security over WEP.
- WPA2: Enhanced security, uses AES encryption.
- WPA3: Latest security protocol, offers stronger encryption and protection against brute-force attacks.

Wireless Configuration Commands (Windows)

- Show available Wi-Fi networks:
  netsh wlan show networks

- Connect to a Wi-Fi network:
  netsh wlan connect name=""

- Disconnect from a Wi-Fi network:
  netsh wlan disconnect

Wireless Troubleshooting Commands

- Ping the access point:
  ping 

- Check signal strength:
  netsh wlan show interfaces

- View wireless network properties:
  netsh wlan show profile "" key=clear

Common Wireless Issues

- Weak signal: Check distance from the access point, obstacles, and interference.
- Connection drops: Update drivers, check for interference, and signal strength.
- No internet access: Verify DHCP settings, check ISP connection, and router status.

Best Practices for Wireless Networking

- Use WPA3 for better security.
- Select less crowded channels (1, 6, 11 in 2.4 GHz).
- Position access points centrally to optimize coverage.
- Limit SSID broadcasting for sensitive networks.
- Regularly update firmware on access points and routers.

Windows Command Cheat Sheet for Network Engineers

Basic Networking Commands

- Check IP configuration:
  ipconfig

- Release IP address:
  ipconfig /release

- Renew IP address:
  ipconfig /renew

- Display current TCP/IP connections:
  netstat -a

- Show routing table:
  route print

Network Diagnostics

- Ping a host:
  ping 

- Trace the route to a host:
  tracert 

- Check DNS resolution:
  nslookup 

- Check network statistics:
  netstat -s

Network Share and File Commands

- List shared folders:
  net share

- Map a network drive:
  net use : \\\

- Disconnect a network drive:
  net use : /delete

Firewall Configuration

- Check firewall status:
  netsh advfirewall show allprofiles

- Allow a program through the firewall:
  netsh advfirewall firewall add rule name="" dir=in action=allow program=""

- Block a program:
  netsh advfirewall firewall add rule name="" dir=in action=block program=""

Wi-Fi Commands

- Show Wi-Fi profiles:
  netsh wlan show profiles

- Connect to a Wi-Fi network:
  netsh wlan connect name=""

- Disconnect from a Wi-Fi network:
  netsh wlan disconnect

Network Adapter Management

- Show network adapters:
  getmac

- Disable a network adapter:
  netsh interface set interface "" admin=disabled

- Enable a network adapter:
  netsh interface set interface "" admin=enabled

Viewing and Managing Services

- List all services:
  services.msc

- Start a service:
  net start 

- Stop a service:
  net stop

PowerShell Networking Commands

- Check IP configuration:
  Get-NetIPConfiguration

- Get DNS settings:
  Get-DnsClientServerAddress

- Get active network connections:
  Get-NetTCPConnection

Remote Connection

- Remote Desktop connection:
  mstsc /v:

- Establish a remote PowerShell session:
  Enter-PSSession -ComputerName

Linux bash command cheat sheet

2024-10-25T23:48:00.004+05:30

Linux Bash Command Cheat Sheet

File and Directory Commands

- List files:
  ls
- Change directory:
  cd 
- Print working directory:
  pwd
- Create a directory:
  mkdir 
- Remove a directory:
  rmdir 
- Remove a file:
  rm 
- Copy a file:
  cp  
- Move or rename a file:
  mv  
- Display file contents:
  cat 
- Display file contents page by page:
  less

File Permissions

- Change file permissions:
  chmod  
- Change file owner:
  chown :

Text Processing

- Search for a string in a file:
  grep  
- Count lines, words, and characters:
  wc 
- Sort lines in a file:
  sort 
- Display unique lines:
  uniq 
- Replace text in a file:
  sed 's/old_text/new_text/g'

Networking

- Check network configuration:
  ifconfig
- Display current IP address:
  hostname -I
- Ping a host:
  ping 
- Check open ports:
  netstat -tuln
- Trace the route to a host:
  traceroute

Process Management

- List running processes:
  ps aux
- Find a process by name:
  pgrep 
- Kill a process:
  kill 
- Kill a process by name:
  pkill 
- View system resource usage:
  top

System Information

- Show disk usage:
  df -h
- Show memory usage:
  free -h
- Show system uptime:
  uptime
- Show current users:
  who

Package Management (Debian/Ubuntu)

- Update package list:
  sudo apt update
- Upgrade installed packages:
  sudo apt upgrade
- Install a package:
  sudo apt install 
- Remove a package:
  sudo apt remove

Miscellaneous

- Clear terminal screen:
  clear
- Display current date and time:
  date
- Get help for a command:
  man 
- Exit the terminal:
  exit

Bash Command Cheat Sheet

File and Directory Commands

- List files:
  ls
- Change directory:
  cd 
- Print working directory:
  pwd
- Create a directory:
  mkdir 
- Remove a directory:
  rmdir 
- Remove a file:
  rm 
- Copy a file:
  cp  
- Move or rename a file:
  mv  
- Display file contents:
  cat 
- Display file contents page by page:
  less

File Permissions

- Change file permissions:
  chmod  
- Change file owner:
  chown :

Text Processing

- Search for a string in a file:
  grep  
- Count lines, words, and characters:
  wc 
- Sort lines in a file:
  sort 
- Display unique lines:
  uniq 
- Replace text in a file:
  sed 's/old_text/new_text/g'

Networking

- Check network configuration:
  ifconfig
- Display current IP address:
  hostname -I
- Ping a host:
  ping 
- Check open ports:
  netstat -tuln
- Trace the route to a host:
  traceroute

Process Management

- List running processes:
  ps aux
- Find a process by name:
  pgrep 
- Kill a process:
  kill 
- Kill a process by name:
  pkill 
- View system resource usage:
  top

System Information

- Show disk usage:
  df -h
- Show memory usage:
  free -h
- Show system uptime:
  uptime
- Show current users:
  who

Package Management (Debian/Ubuntu)

- Update package list:
  sudo apt update
- Upgrade installed packages:
  sudo apt upgrade
- Install a package:
  sudo apt install 
- Remove a package:
  sudo apt remove

Miscellaneous

- Clear terminal screen:
  clear
- Display current date and time:
  date
- Get help for a command:
  man 
- Exit the terminal:
  exit

BGP (Border Gateway Protocol) Cheat Sheet

2024-10-25T23:47:00.002+05:30

BGP (Border Gateway Protocol)

Cheat Sheet

Basic Concepts

- BGP (Border Gateway Protocol): The protocol used to exchange routing information between different autonomous systems (AS).
- Autonomous System (AS): A collection of IP networks and routers under a single organization's control.
- BGP Peers: Routers that exchange BGP routing information.
- BGP Session: TCP connection between BGP peers (port 179).

BGP States

1. Idle
2. Connect
3. Active
4. OpenSent
5. OpenConfirm
6. Established

BGP Attributes

- AS_PATH: List of ASs a route has traversed.
- NEXT_HOP: Next hop IP address for the route.
- LOCAL_PREF: Indicates the preferred exit point from the AS.
- MED (Multi-Exit Discriminator): Suggests preferred entry point to an AS.
- COMMUNITY: A way to group routes for routing decisions.

BGP Configuration Commands (Cisco)

Basic Configuration:
router bgp 
  neighbor  remote-as 
  neighbor  description 

Example:
router bgp 65001
  neighbor 192.168.1.1 remote-as 65002
  neighbor 192.168.1.1 description "Peer Router"

Advertise a Network:
network  mask 

Example:
network 10.0.0.0 mask 255.255.255.0

Viewing BGP Information (Cisco)

- Show BGP Summary:
show ip bgp summary

- Show BGP Routes:
show ip bgp

- Show BGP Neighbor Details:
show ip bgp neighbors

BGP Route Filtering

- Disallow Specific Routes:
neighbor  filter-list  in

- Using Route Maps:
route-map  permit 
  match 
  set

BGP Timers

Adjust BGP Keepalive and Hold Timers:
neighbor  timers  

Example:
neighbor 192.168.1.1 timers 30 90

BGP Best Path Selection Criteria

1. Highest Weight (Cisco-specific)
2. Highest Local Preference
3. Shortest AS Path
4. Lowest Origin Type (IGP < EGP < Incomplete)
5. Lowest MED
6. EBGP over IBGP
7. Lowest IGP metric to NEXT_HOP
8. Oldest route (if all else is equal)
9. Lowest BGP router ID (if all else is equal)

Common BGP Commands for Troubleshooting

- Check BGP Neighbors:
show ip bgp neighbors

- BGP Route Information:
show ip bgp 

- Check BGP Updates:
show ip bgp updates

BGP Cheat Sheet

Basic Concepts

- BGP (Border Gateway Protocol): The protocol used to exchange routing information between different autonomous systems (AS).
- Autonomous System (AS): A collection of IP networks and routers under a single organization's control.
- BGP Peers: Routers that exchange BGP routing information.
- BGP Session: TCP connection between BGP peers (port 179).

BGP States

1. Idle
2. Connect
3. Active
4. OpenSent
5. OpenConfirm
6. Established

BGP Attributes

- AS_PATH: List of ASs a route has traversed.
- NEXT_HOP: Next hop IP address for the route.
- LOCAL_PREF: Indicates the preferred exit point from the AS.
- MED (Multi-Exit Discriminator): Suggests preferred entry point to an AS.
- COMMUNITY: A way to group routes for routing decisions.

BGP Configuration Commands (Cisco)

Basic Configuration:
router bgp 
  neighbor  remote-as 
  neighbor  description 

Example:
router bgp 65001
  neighbor 192.168.1.1 remote-as 65002
  neighbor 192.168.1.1 description "Peer Router"

Advertise a Network:
network  mask 

Example:
network 10.0.0.0 mask 255.255.255.0

Viewing BGP Information (Cisco)

- Show BGP Summary:
show ip bgp summary

- Show BGP Routes:
show ip bgp

- Show BGP Neighbor Details:
show ip bgp neighbors

BGP Route Filtering

- Disallow Specific Routes:
neighbor  filter-list  in

- Using Route Maps:
route-map  permit 
  match 
  set

BGP Timers

Adjust BGP Keepalive and Hold Timers:
neighbor  timers  

Example:
neighbor 192.168.1.1 timers 30 90

BGP Best Path Selection Criteria

1. Highest Weight (Cisco-specific)
2. Highest Local Preference
3. Shortest AS Path
4. Lowest Origin Type (IGP < EGP < Incomplete)
5. Lowest MED
6. EBGP over IBGP
7. Lowest IGP metric to NEXT_HOP
8. Oldest route (if all else is equal)
9. Lowest BGP router ID (if all else is equal)

Common BGP Commands for Troubleshooting

- Check BGP Neighbors:
show ip bgp neighbors

- BGP Route Information:
show ip bgp 

- Check BGP Updates:
show ip bgp updates

Python Cheat Sheet

2024-10-25T23:44:00.004+05:30

Python Cheat Sheet

Basic Syntax

# Comments 
# This is a comment

# Variables 
x = 5
name = "Alice"

# Data Types 
integer = 10
float_num = 10.5
string = "Hello"
boolean = True
list_example = [1, 2, 3]
tuple_example = (1, 2, 3)
dict_example = {"key": "value"}

Control Structures

# If Statements
if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

# Loops
# For Loop
for i in range(5):
    print(i)

# While Loop
while x < 5:
    x += 1

Functions

# Defining Functions
def my_function(param1, param2):
    return param1 + param2

# Lambda Functions
square = lambda x: x ** 2

Data Structures

# Lists
my_list = [1, 2, 3]
my_list.append(4)

# Dictionaries
my_dict = {"name": "Alice", "age": 25}
age = my_dict["age"]

# Sets
my_set = {1, 2, 3}
my_set.add(4)

# Tuples
my_tuple = (1, 2, 3)

List Comprehensions

squares = [x ** 2 for x in range(10)]

String Methods

# Common Methods
my_string = "Hello, World!"
my_string.lower()
my_string.upper()
my_string.split(", ")

File Handling

# Reading a File
with open('file.txt', 'r') as file:
    content = file.read()

# Writing to a File
with open('file.txt', 'w') as file:
    file.write("Hello, World!")

Exception Handling

try:
    # Code that may raise an exception
    result = 10 / 0
except ZeroDivisionError:
    print("You can't divide by zero!")
finally:
    print("This will always execute.")

Modules and Packages

# Importing Modules
import math
from datetime import datetime

Decorators

def my_decorator(func):
    def wrapper():
        print("Before the function.")
        func()
        print("After the function.")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")

Generators

def countdown(n):
    while n > 0:
        yield n
        n -= 1

for number in countdown(5):
    print(number)

Common Built-in Functions

# len(), sum(), max(), min(), sorted(), enumerate()

Useful Libraries

# NumPy, Pandas, Matplotlib, Requests, Flask/Django

Common Commands

# Install a Package
pip install package_name

# Run a Python Script
python script.py

Python Cheat Sheet

Basic Syntax

# Comments 
# This is a comment

# Variables 
x = 5
name = "Alice"

# Data Types 
integer = 10
float_num = 10.5
string = "Hello"
boolean = True
list_example = [1, 2, 3]
tuple_example = (1, 2, 3)
dict_example = {"key": "value"}

Control Structures

# If Statements
if x > 0:
    print("Positive")
elif x < 0:
    print("Negative")
else:
    print("Zero")

# Loops
# For Loop
for i in range(5):
    print(i)

# While Loop
while x < 5:
    x += 1

Functions

# Defining Functions
def my_function(param1, param2):
    return param1 + param2

# Lambda Functions
square = lambda x: x ** 2

Data Structures

# Lists
my_list = [1, 2, 3]
my_list.append(4)

# Dictionaries
my_dict = {"name": "Alice", "age": 25}
age = my_dict["age"]

# Sets
my_set = {1, 2, 3}
my_set.add(4)

# Tuples
my_tuple = (1, 2, 3)

List Comprehensions

squares = [x ** 2 for x in range(10)]

String Methods

# Common Methods
my_string = "Hello, World!"
my_string.lower()
my_string.upper()
my_string.split(", ")

File Handling

# Reading a File
with open('file.txt', 'r') as file:
    content = file.read()

# Writing to a File
with open('file.txt', 'w') as file:
    file.write("Hello, World!")

Exception Handling

try:
    # Code that may raise an exception
    result = 10 / 0
except ZeroDivisionError:
    print("You can't divide by zero!")
finally:
    print("This will always execute.")

Modules and Packages

# Importing Modules
import math
from datetime import datetime

Decorators

def my_decorator(func):
    def wrapper():
        print("Before the function.")
        func()
        print("After the function.")
    return wrapper

@my_decorator
def say_hello():
    print("Hello!")

Generators

def countdown(n):
    while n > 0:
        yield n
        n -= 1

for number in countdown(5):
    print(number)

Common Built-in Functions

# len(), sum(), max(), min(), sorted(), enumerate()

Useful Libraries

# NumPy, Pandas, Matplotlib, Requests, Flask/Django

Common Commands

# Install a Package
pip install package_name

# Run a Python Script
python script.py

IEEE 802.1x (Dot1x) authentication and device-sensor configuration template for Cisco 3650

2024-06-07T17:47:00.000+05:30

Configure dot1x

// Enable aaa//

!
aaa new-model

// Create local username password for admin authentication //

username admin privilege 15 secret admin1

enable secret admin1

aaa authentication login default local
aaa authentication enable default enable
aaa authorization exec default local

// Define radius server, ISE server ip = 10.10.10.10//

radius server ise-psn01
address ipv4 10.10.10.10 auth-port 1812 acct-port 1813
key Cisco123

// Create ISE group//

aaa group server radius ISE

server name ise-psn01

// AAA configuration for dot1x authentication //

aaa authentication dot1x default group ISE

aaa authorization network default group ISE

aaa accounting dot1x default start-stop group ISE

ip radius source-interface Vlan10

//Enable dot1x globally //

dot1x system-auth-control

// for Change of Authorization (CoA)" messages from the RADIUS server.//

aaa server radius dynamic-author

client 10.10.10.10 server-key Cisco123

// Interface configuration //

interface GigabitEthernet1/0/1

switchport access vlan 88

switchport mode access

switchport voice vlan 118

switchport port-security maximum 2

switchport port-security

spanning-tree portfast

spanning-tree bpduguard enable

authentication host-mode multi-auth

dot1x pae authenticator

authentication order dot1x mab

authentication priority dot1x mab

authentication port-control auto

mab

authentication event fail action next-method

dot1x timeout tx-period 2

end

PAE = port access entity

#############################################################

Configure Device Sensor

device-sensor accounting

device-sensor notify all-changes

radius-server vsa send accounting

// Creates a TLV list and enters DHCP-LIST sensor configuration mode, where you can configure individual TLVs. //

device-sensor filter-list dhcp list dhcp-list

option name host-name

option name domain-name

option number 50

Note: DHCP option 50 is used to let clients request a specific IP address ;

// Creates a TLV list and enters CDP sensor configuration mode, where you can configure individual TLVs.//

device-sensor filter-list cdp list cdp-list

tlv name device-name

tlv name address-type

tlv number 34

// Creates a TLV list and enters LLDP sensor configuration mode, where you can configure individual TLVs.//

device-sensor filter-list lldp list lldp-list

tlv name chassis-id

tlv name management-address

tlv number 28

Command to verify

Switch # sh device-sensor details

Switch #sh device-sensor cache all

Switch # sh device-sensor cache int g1/0/1

Switch # sh device-sensor cache mac <mac-address>

CCNP Quick notes

2024-02-17T22:03:00.003+05:30

CoPP

Control Plane Policing (CoPP) is a network security feature used in Cisco devices and other network equipment to protect the control plane of the device. The control plane is responsible for managing and maintaining the device's routing and switching functions, it works like Brain of network device. Protecting the control plane is essential to ensure the stability and security of a network device.

Control Plane Policing is designed to prevent unauthorized or malicious traffic from overwhelming the control plane and causing network disruptions. It involves setting limits on the amount of traffic that the control plane can process, effectively creating a policing mechanism for control plane traffic. When traffic exceeds the configured limits, CoPP can either drop or rate-limit the excess traffic to protect the control plane.

Key components of Control Plane Policing include:

Access Control Lists (ACLs): CoPP uses access control lists to define which types of traffic are allowed or denied access to the control plane. ACLs can be configured to match specific protocols, ports, or source/destination IP addresses.
Rate Limiting: CoPP enforces rate limits on control plane traffic. This ensures that the control plane only processes a specific amount of traffic within a given time frame.
Class Maps and Policy Maps: Control Plane Policing uses class maps and policy maps to define the traffic classification and policing actions. Class maps specify the criteria for identifying traffic, and policy maps define how the traffic is policed.
Logging and Monitoring: CoPP typically provides logging and monitoring capabilities so that network administrators can track control plane traffic and any actions taken by the CoPP feature.

Difference between conform-action, exceed-action and violate-action in control plane policing

In Control Plane Policing (CoPP), "conform-action," "exceed-action," and "violate-action" are actions that specify what should happen to different types of traffic based on whether they conform to, exceed, or violate the configured traffic rate limits. These actions are used to control and manage traffic that is being policed by CoPP.

Here's an explanation of each of these actions:

Conform-Action: This action is applied to traffic that conforms to the configured rate limits. In other words, when traffic falls within the permitted rate, it "conforms." The "conform-action" specifies what should happen to this traffic. Typically, conforming traffic is allowed to pass through without any additional restrictions. It's considered acceptable and within the defined policing parameters.
Exceed-Action: This action is applied to traffic that exceeds the configured rate limits but doesn't violate them. When traffic exceeds the specified rate but is still within the defined excess rate, the "exceed-action" determines what should happen. Common actions for exceeding traffic include dropping it or remarking the traffic to a lower priority or a different class of service. The idea is to handle this traffic less favorably than conforming traffic but not as harshly as violating traffic.
Violate-Action: This action is applied to traffic that violates the configured rate limits. When traffic exceeds the maximum rate allowed, it is considered a "violation." The "violate-action" specifies how to handle this traffic. Typically, violating traffic is either dropped or remarked to a lower priority or a different class of service. Violating traffic is generally the least desirable and may be associated with potential threats or attacks.

IPSLA

IPSLA, or Cisco IOS IP Service Level Agreements, is a feature in Cisco routers and switches that allows network administrators to measure, verify, and report on network performance.

ip sla 1 icmp-echo <target IP> frequency 60 exit

ip sla schedule 1 life forever start-time now

show ip sla statistics 1

EEM

Cisco Embedded Event Manager (EEM) is a powerful and flexible subsystem available on Cisco devices that allows you to monitor events and take automated actions in response. EEM provides a scripting language that allows you to define policies to respond to events on the device.

Basic Concepts:

Event: An event is a significant occurrence or a state change that can trigger an action. Events can be related to system-level changes, interface status, SNMP traps, syslog messages, etc.
Policy: A policy is a set of rules that define what action should be taken when a specific event occurs.
Action: An action is a task or command that is executed when a policy is triggered by an event.

Steps to Create a Basic EEM Script:

Enter EEM Configuration Mode:

enable

configure terminal

event manager applet <applet_name>

Define the Event:

event <event_type> <event_name>

Specify the Action:

action <action_type> <action_command>

Exit Configuration Mode &

Save Configuration:

Example of EEM

enable configure terminal event manager applet InterfaceUpDown event syslog pattern "LINK-3-UPDOWN" occurs 1 action 1.0 syslog priority emergencies msg "Interface is down - taking action" exit write memory

Interview question on Cisco EEM?

What is Cisco EEM?
Answer: Cisco EEM, or Embedded Event Manager, is a feature embedded in Cisco devices that provides a scripting interface for monitoring events and taking automated actions in response to those events.
What are the key components of an EEM policy?
Answer: An EEM policy consists of an event, a trigger that specifies when the policy should be executed, and an action, which defines the tasks or commands to be performed when the event occurs.
Can you give an example of an event in EEM?
Answer: An example of an event is "event syslog pattern," where a policy is triggered based on a specific pattern in syslog messages.
How do you create a basic EEM policy?
Answer: Use the event manager applet configuration mode, define an event using the event command, and specify actions using the action command.
What is the purpose of the occurs keyword in an EEM policy?
Answer: The occurs keyword specifies how many times an event must occur before the associated actions are executed. For example, occurs 1 means the actions will be triggered on the first occurrence of the event.
Explain the use of the poll-interval keyword in an SNMP-related EEM event.
Answer: The poll-interval keyword sets the interval at which an SNMP query is repeated. It defines how often the device checks the specified SNMP variable for changes.
How can you view the existing EEM policies on a Cisco device?
Answer: Use the show event manager policy registered command to view a list of registered EEM policies.
What is the difference between an EEM applet and an EEM script?
Answer: An EEM applet is a simple and single-shot policy, while an EEM script is a more complex and reusable set of policies. An EEM script can contain multiple applets.
Can you explain the importance of error handling in EEM policies?
Answer: Error handling is crucial to ensure the robustness of EEM policies. Proper error handling helps prevent unintended consequences and ensures that the device behaves predictably even in the face of unexpected conditions.
How do you troubleshoot EEM policies that are not working as expected?
Answer: Use the show event manager policy registered and show event manager policy registered detail commands to check the status and details of registered policies. Additionally, examine the syslog messages for any errors or debug EEM events using the debug event manager action cli command.

NetFlow

NetFlow is a network protocol developed by Cisco Systems for collecting IP traffic information and monitoring network traffic flow. It provides a way to collect and analyze data about the traffic flowing through a router or switch, allowing network administrators to gain insights into network utilization, identify performance issues, and enhance security. NetFlow is widely used in various network environments, including enterprise networks, service provider networks, and data centers.

Here are the key concepts and components of NetFlow:

Flow: In NetFlow, a flow is a unidirectional sequence of packets that share common characteristics. It include source and destination IP addresses, source and destination port numbers, protocol, and the type of service. The flow is the basic unit of measurement in NetFlow.
Flow Record: A flow record is a collection of key fields that define a flow. It include source and destination IP addresses, source and destination port numbers, protocol, and other relevant information. Flow records are used to store information about individual flows.
Flow Exporter: A flow exporter is responsible for aggregating flow records and exporting them to a NetFlow collector for further analysis. The exporter formats the flow records and sends them to the collector using the NetFlow protocol (typically UDP).
Flow Collector: The flow collector is a system or software that receives and stores the flow records sent by flow exporters. It is responsible for processing and analyzing the collected data. NetFlow collectors can provide insights into network traffic patterns, usage, and potential issues.
Flow Sampler: In some cases, not all packets are included in the NetFlow data to reduce the processing load on routers and switches. Flow samplers are mechanisms used to sample a subset of packets to estimate the characteristics of the entire flow.
NetFlow Versions: There are different versions of the NetFlow protocol, such as NetFlow v5, v9, and IPFIX (which is similar to NetFlow v9 and standardized by the IETF). Each version may have additional features and improvements over the previous ones.

Netflow configuration example:

# Enable NetFlow on an interface

interface GigabitEthernet0/0

ip flow ingress

# Configure the NetFlow exporter

ip flow-export destination <collector-ip> <collector-port>

ip flow-export version 9

Brief history of Authentication protocol

2024-02-17T21:46:00.007+05:30

Authentication protocol evolution timeline:

Authentication protocol evolution.

PAP standardized in 1992 by way of IETF Request for Comments 1334. Used for Point-to-Point Protocol (PPP) authentication methods,
CHAP August 1996
MS-CHAP 1996
EAP introduced in 1996 as an extension to the Point-to-Point Protocol (PPP).
EAP-MSCHAPv2 (MS in 1999)
LEAP - 2000 Cisco for wireless
EAP-TLS Year 2000 Microsoft and Cisco contributed but it is open standard protocol
EAP-TTLS introduced by Funk Software in 2001
LEAP- was introduced by Cisco Systems in 2003. FAST Lightweight Extensible Authentication Protocol - Flexible Authentication via Secure Tunneling)
PEAP (potected EAP) - created by RSA, MS and Cisco in 2003
EAP-GTC (Generic Token Card) Cisco Systems in 2004.
TEAP (Tunneled Extensible Authentication Protocol) was introduced by Cisco Systems in 2007.

EAP Chaining:

EAP (Extensible Authentication Protocol) chaining refers to a method of using multiple EAP methods sequentially during the authentication process.
In EAP chaining, each EAP method used in the chain performs a specific authentication task, such as user authentication, key exchange, or certificate validation. The output of one EAP method serves as input to the next EAP method in the chain.

EAP type:

There are two types of EAP Native EAP and Tunneled EAP.

Native

EAP-MD5 (Extensible Authentication Protocol - Message Digest 5) was introduced in 1996
EAP-TSL (Extensible Authentication Protocol-Transport Layer Security)
EAP-MSCHAPv2 (MS in 1999)
EAP-GTC (Generic Token Card) Cisco Systems in 2004.

Tunneled EAP (uses outer tunnel with inner Native EAP protocol)

PEAP (Protected EAP)
EAP-FAST (Flexible Authentication with Secure Tunnel)

Protocol to support AAA:

RADIUS

RADIUS (Remote Authentication Dial-In User Service) protocol was was originally developed by Livingston Enterprises (Later became part of Lucent Technologies) in 1991 as a way to manage and authenticate users accessing dial-up networks.
In 1997 Internet Engineering Task Force (IETF) later standardized RADIUS protocol in RFC 2058 and RFC 2059.

TACACS / TACACS+

TACACS (Terminal Access Controller Access-Control System) protocol was introduced by BBN Technologies in the 1980s. IT was a proprietary protocol to provide centralized
authentication, authorization, and accounting (AAA) services for managing network access to UNIX-based systems.
The original TACACS protocol was later replaced by TACACS+ (TACACS Plus) by Cisco Systems in the mid-1990s.
TACACS+ introduced improvement by adding support for more features and enhanced security mechanisms.

How various authentication protocol works.

Password Authentication Protocol (PAP):

PAP was one of the earliest authentication protocols used in networking.
It sends usernames and passwords in plain text, making it vulnerable to eavesdropping attacks.

Challenge-Handshake Authentication Protocol (CHAP):

CHAP was introduced as a more secure alternative to PAP.
It uses a challenge-response mechanism to authenticate users, protecting against replay attacks.

Extensible Authentication Protocol (EAP):

EAP was introduced to provide a framework for supporting multiple authentication methods within network protocols.
It allows for flexibility and interoperability by enabling the use of various authentication mechanisms.

Protected Extensible Authentication Protocol (PEAP):

PEAP is an extension of EAP that provides a secure authentication framework by establishing a TLS tunnel for authentication.
It protects against eavesdropping and man-in-the-middle attacks by encrypting authentication credentials.

EAP-TLS (EAP-Tunneled Transport Layer Security):

EAP-TLS uses TLS to provide mutual authentication between clients and servers using digital certificates.
It offers strong security features, including mutual authentication and encryption of communication.

Microsoft Challenge Handshake Authentication Protocol version 2 (MS-CHAPv2):

MS-CHAPv2 is a proprietary authentication protocol developed by Microsoft.
It is commonly used within the EAP framework for VPN connections and supports mutual authentication.

Tunneled Extensible Authentication Protocol (TEAP):

TEAP is an extension of EAP designed for use in wireless networks.
It provides enhanced security and flexibility by allowing the encapsulation of multiple EAP methods within a single authentication conversation.

Biometric Authentication:

Biometric authentication methods, such as fingerprint scanning and facial recognition, have become increasingly popular for user authentication.
They offer convenience and strong security by using unique biological characteristics for authentication.

Two-Factor Authentication (2FA) and Multi-Factor Authentication (MFA):

2FA and MFA combine multiple authentication factors, such as passwords, biometrics, and one-time codes, to enhance security.
They provide an additional layer of protection against unauthorized access.

OAuth and OpenID Connect:

OAuth and OpenID Connect are modern authentication protocols commonly used for web-based authentication and authorization.
They enable secure access to resources across different websites and applications without sharing passwords.

Infoblox

2023-06-23T13:17:00.010+05:30

Infoblox

Deploy Infoblox DDI VM on VmWare

Lab setup

· We have two node deployment.

o Hostname: ns1.lab-net.in IP Addresss:192.168.0.31

o Hostname: ns2.lab-net.in IP Addresss:192.168.0.32

· Create two VIM using NIOS ova (nios-8.5.2) on ESXi-8

Step 1: Create Infoblox vm Using OVA.

Wait till VM is created successfully.

Step 2: Access VM console (Setup ip)

First time Infoblox VM console login:

Username: admin

Password: infoblox

Set ip for node using command > set networks

Step 2: Setup 90 day evaluation license.

· Once node restart, re-login and set license. Using command > set temp_licenese

o Do it two time one for service license and 2^nd time nios license.

Infoblox> set temp_license

STEP 3: Login to GUI of node 1 (ns1 / 192.168.0.31)

Run Grid setup wizard

· Login into 1^st node ns1 and run through Grid setup wizard.

Note: Don’t change date and time only set time zone. Changing time cause temporary license to expire.

Keep it default.

Relogin with new password.

Step 2: Setup 2^nd node (ns2 / 192.169.0.32)

Setup similar to nod1, but once it online don’t run grid setup wizard, just keep grid and node name default.

Setup summary:

Set ip
Set license
Verify Gui access (node is is default grid : Infoblox, and hostname is infoblox@local.doman

https://192.168.0.32/

Just note that 2^nd node has default grid name and hostname.

Now go to Primary Node and add 2^nd node to grid

Now access 2^nd node console

Verify status on master node ns1

Note: now onwards even if you try to access url 2 node ns2, it will redirect to primary node ns1.

Enable dhcp dns service

Same for DNS service

Configure DNS setting

Adding dns entries

ESXi8 on NUC 12

2023-05-05T14:56:00.022+05:30

Installing ESXi8 on NUC 12

Before we start take a note of two thing you should understand before installing ESXi on NUC

Issue 1: Intel CPU architecture change:

ESXi is not aware of the big.LITTLE CPU architecture that contains dedicated P/E cores.

This result in PSOD (Purple Scree Of Death) when try to install vmware on NUC12

Work around for this is either

Solution 1: Disable E-Core on NUC

Solution 2: You have to apply ESXi kernel boot option:

cpuUniformityHardCheckPanic=FALSE to allow ESXi to boot and install

Issue 2: Intel NIC

ESXi version 7.0 and older does not have the Intel i225-V driver used in NUC.

Solution 1: We have Community networking driver for ESXi that you can download from the VMware & customize the ISO for a successful install.

Solution 2: we can use ESXi8

ESXi 8.0 version will have the driver for this NIC, so we can use it without customizing.

Hardware & software used:

Intel NUC 12 Pro (Wall Street Canyon) with 1Tb NVME and 64 Gb DDR 4 Ram
VMware ESXi 8.0 ISO image
Rufus
Keyboard, HDMI monitor & USB flash drive ( minimum 8Gb ), network cable and laptop.

Installation process:

Step 1: Set & Verify Intel NUC 12.

Step 2: Login into VMware website using registered account. Download ESXi8 iso file & note license key.

Step 3: Create bootable flash drive using rufus.

Step 4: Installing VMWare8 on NUC 12

· Since we are using VMWare8 we only need work around for CPU architecture mentioned above. This id done by applying kernel option.

· · Insert USB with image into NUC and power on.

· · During boot up of ESXi installer , press Shift + O

· · Type following

o cpuUniformityHardCheckPanic=FALSE

· Press Enter to continue

· Accept EULA pressing F11

· It will ask to select storage device for installation, please select storage and press enter to continue

· · Select keyboard language (default US )

· Set root password

· Warning message: This disk will be repartitioned, press F11 to install.

· installation will progress showing progress bar.

· Message to remove installation media before reboot : Before rebooting we need to add kernel option again so that it boot up successfully again after installation.

· To update option Press ALT + F1, it will prompt for login (user root & password blank)

· Enter ESXi shell and edit following file using vi exitor

o Vi /vmfs/volumes/BOOTBANK1/boot.cfg

o Update option for kernalopt, append following

§ cpuUniformityHardCheckPain=FALSE

§ save file

· Press ALT + F2 to go back to reboot prompt

· reboot esxi by removing bootable flash drive.

· Esxi will reboot and wait for dhcp configuration. We can set ip setting manually using F2 key

· To permanently configure the ESXi kernel boot setting so that setting retain after future update/upgrade. Set the kernel setting using ESXCLI.

o To do this first login to DCUI (Direct Console User Interface) by pressing F2 and then

o Navigating to Troubleshooting Option and enable ESXi Shell (Press Enter key to enable or disable option).

· Switch into the ESXi shell by pressing ALT+F1 and login with root and the password you had configured during installation.

· Now run the following ESXCLI command to configure the kernel option:Exscli system settings kernel set -s cpuUniformityHardCheckPain -v FALSE

· Verify

Exscli system settings kernel list -0 cpuUniformityHardCheckPain

· Now you are read to plug network cable from laptop to nuc and open Gui interface for esxi8 console.

Thanks to William Lam for sharing his great work on installation procedure with workaround.

Reference link.

https://williamlam.com/2022/09/esxi-on-intel-nuc-12-pro-wall-street-canyon.html

Introduction to INTEL NUC 12 PRO

2023-05-03T16:30:00.003+05:30

What is Intel NUC?

NUC = Next Unit of Computing, it is small factor integrated cpu.

It comes with i7, i5 or i3 processor.

Model we are discussing here is NUC12WSHI5

Following is NUC12 pro with i5 processor.

This is 12th Gen (Alder Lake) device comes with separate Performance core and Efficient core, known as P-core and E-core. In NUC12WSHI5 there are 4 P-core (with 8 thread) and 8 -E-core (with 8 thread) so you get system with 12 Cores and 16 Threads. Nick name for NUC 12 is Wall Street Canyon.

NUC barebone comes with Intel Wi-fi 6E AX211 (Gig+) and Bluetooth Generation 5 but need RAM and Storage.

It support DDR4 max and has 2 slot, support max 64Gig memory

For storage we can use SATA or NVME PCIe-Gen 4 SSD

We get power brick with system, but need to get power cable separately.

2022-10-12T10:07:00.008+05:30

VPN:

IPSEC

· It is protocol suit based on IETF (Internet Engineering Task Force) standard used together to setup encrypted connection between devices.

· Used to connect private network over internet = VPN (Virtual Private Network)

· Operate in two modes: Transport mode & Tunnel modes

IPSec provides:

ü confidentiality,

ü peer authentication,

ü data integrate,

ü replay protection and

ü access control.

Problem with IPSec it reduces throughput of network over 80%, NAT has issue to overcome we use NAT-traversal.

ESP & AH

Subprotocol of IPSEC

· ESP (Encapsulation Security Payload): provide encryption service to IPSec / IP

o Confidentiality, limited non-repudiation (since it doesn’t encrypt IP header)

o Encrypt IP payload (data) not IP header.

o End to End security (between client to server or site to site)

o ESP can be used in tunnel or transport mode

§ Tunnel mode: between two gateways. It encrypts all data IP header and all data above it.

§ In transport mode it encrypts only IP payload and not header. Both sides should be host.

o NIDS (Network intrusion detection system) can monitor traffic before tunnel, in transport mode we use HIDS (Host based Intrusion Detection System)

o ESP can be used with or without AH, in tunnel mode we use ESP with AH and without AH in transport mode.

· AH (provide connectionless integrity)

o Both data integrity and source integrity combine into non-repudiation where sender of packet cannot deny that he has not send this packet.

o AH don’t provide confidential

o Only used in tunnel mode

o Issue with AH as it encrypts IP header

ESP provide encryption from data in layer L4 and L7

AH added new IP header

Security = encryption + integrity + authentication

Encryption user keys (aes / 3des)

Integrity uses hash (Cisco support sha and md5)

ISAKMP

Entire security lies in creating and exchanging key, by using one the method bellow.

1. Use public shared key and send to other 3^rdparty

2. Use static key

3. Key exchange algorithm (public, private key pair)

Key is exchanged on ISAKMP (Internet security association key management protocol)

· It is framework to create Security SA and key exchange.

· Used to carry messages for IKE

· Used for negotiating, establish, modify, and delete security association (SA) and related parameter.

· Used for denial-of-service protection

· ISAKMP don’t exchange key, actual key exchange is done using

o Pre-shared through IKE

o KINK (Kerberized Internet Negotiation of keys , where we used 3^rd party KDC (Key Distribution Center) for distributing of keys between two endpoints.

o IPSECKEY Resource Record (RR) where public keys of domains are published. It uses DNSSEC (DNSSecurity)

§ Security Association (SAs) are session parameters for AH and ESP

§ SPI (Security parameter index) which is of 32, which denote the SA

§ It is simplex, we must create two SA for ESP and 2 SA for AH in each direction (inbound and outbound)

IKE (Internet Key Exchange)

§ IKE is used to setup security association

§ Based on X.509 digital certificate for authentication

§ This can be pre-shared or shared through DNS

§ UDP 500 and 4550 (when NAT is used)

§ There are two phases in IKE

o Phase I:

§ ISAKMP SA using Diffie-Hellman (DH) for key exchange.

§ It is management traffic to establish a policy for IPSec devices

§ Bidirectional (single security association for both side)

o Phase II:

§ IPSec SA are established

§ For data protection

§ Simplex / Unidirectional (Two SA for each direction)

o Highest protocol will be used by IKE. E.g., DES (Data Encryption Standard) will be superseded AES (Advanced Encryption Standard)

Phase 1 = ISAKMP SA = Mgmt. (1-bidirectional)

Phase 2 = IPSec SA = Data (2-unidirectional)

IKE Modes

§ Main mode (3 X two-way exchanges)

o 1^stexchange: Proposal algorithm and hash

o 2^nd exchange: DH to generate shared key

o 3^rd exchange: Peer identity = IP, FQDN

§ Aggressive mode (fewer exchange), faster than main mode

§ Quick mode: used in Phase II to build IPSec SA

IKE Version

IKEv1

§ 9 / 6 message based on mode main or aggressive.

§ NAT will not work, we must enable NAT-Traversal

§ DPD (Dead Peer Detection) need to be enabled manually

§ Don’t support EAP authentication

§ Support symmetric authentication (use same method / pre-shared key on both side)

IKEv2

§ Less bandwidth and less message exchange

§ Following components are built-in

o ISAKMP, AH/ESP, ISP DOI, DPD, NAT-T, mode config

o Uses single phase

o Has only two messages: Mandatory and optional

§ Support EAP (Extensible Authentication protocol) along with pre-shared key and certification authentication

Note: EAP allow to use LAN authentication method like AD or ISE integration

§ Support asymmetric authentication method

Note: Asymmetric authentication: different pre-shared key on both side or different method like pre-shared on one side and certificate on other

§ Support MOBIKE (mobility and multi homing protocol), instant connection on network change (e.g., IP change when we move in Wi-Fi coverage)

Note: MOBIKE e.g., VPN don’t drop when we connect from Wi-Fi to 4G or different network.

§ IKEv2 support more stronger encryption but still faster

§ Support PFS (Perfect forward Secrecy)

Note: PFS feature: force to use different key in PHASE I and PHASE II (re-keying mechanism)

§ Facility to negotiate multiple sets of selectors

For IKEv1 interesting traffic is defined using ACL and it’s limited to IP and port number.

§ Better reliability through improved sequence numbers and acknowledgments.

ISAKMP SA State for IKE Main Mode SA Negotiation.

· MM_NO_STATE: ISAKMP SA has been created but nothing else has happened yet. “larval” at this state- there is no state

· MM_SA_SETUP: Peers have agreed on parameters for the ISAKMP SA.

· MN_HEY_EXCH: Peer exchanged DH public keys and have generated a shared secret. ISAKMP SA remains unauthenticated

· MM_KEY_AUTH: the ISAKMP SA has been authenticated. If the router initiated these exchanges, this state transition immediately to QM_IDLE and Quick Mode exchange begins.

ISAKMP SA State for IKE Aggressive mode SA Negotiation.

· AG_NO_STATE: ISAKMP SA has been created, but nothing else has been happened yet. There is not state.

· AG_INIT_EXCH: the peers have done the first exchange in Aggressive Mode, but the SA is not authenticated.

· AG_AUTH: peers have done the first exchange in Aggressive mode, but the SA is not authenticated.

DMVPN

DMVPN= mGRE + IPSec + NHRP

GRE (Generic Routing Encapsulation)

· Simple non-negotiated tunnel

· Protocol number 47

· 4-to-8-byte header + new ip header

· P2P GRE, P2M mGRE

· To configure P2P GRE

o Tunnel ip

o Tunnel source

o Tunnel destination

o Key

· To configure mGRE

o Ip address

o Tunnel source

o Tunnel key

o Nhrp (instead of tunnel destination)

· NBMA Address (non-broadcast multi access address) is WAN ip.

NHRP: (RFC 2332)

· Allows peer to have dynamic ip

· L2 protocol

· Map tunnel / vpn address to NBMA address

· Multicast traffic are sent to specific remote peer.

· NHRP config

o Ip nhrp network-id <id>

o Ip nhrp map <vpn-tunnel-ip> <Nbma-address>

o Ip nhrp map multicast <NBMA-Address>

Ip nhrp map multicast dynamic

o Ip nhrp nhs <vpn-tunnel-ip>

· NHRP cache population

o Manual / static

o Registration (hub learn spoke)

o Resolution

How DMVPN work:

· Spoke router report (local IP) to Hub and join multi-point GRE network.

· When spoke want to talk to another spoke it send nhrp request to hub.

DMVPN Advantage:

· Don’t need static IP

· Scalable solution

· Device build up tunnel dynamically

LAB 1: SITE-to-SITE vpn ikev1

Topology

STEP to create ikev1 Site-to-Site vpn tunnel:

1. Create pre-share key

2. Create crypto isakmp policy (authentication, encryption, hash, and group)

3. Create IPsec transform-set

4. Create ACL to define interesting traffic

5. Create crypto map (set peer, transform-set, ACL-interesting traffic)

6. Create tunnel (source, destination, and mode gre IP)

7. Apply crypto ma to WAN interface

R1 Config

crypto isakmp key cisco123 address 192.168.2.2

crypto isakmp policy 2

encr 3des

hash md5

authentication pre-share

group 2

crypto ipsec transform-set TS esp-3des esp-md5-hmac

ip access-list extended GRE

permit ip any any

crypto map CRYPTOMAP 10 ipsec-isakmp

set peer 192.168.2.2

set transform-set TS

match address GRE

interface Tunnel0

ip address 172.16.1.1 255.255.255.0

ip mtu 1400

tunnel source Ethernet1/0

tunnel destination 192.168.2.2

int eth 1/0

ip address 192.168.1.1 255.255.255.0

crypto map CRYPTOMAP

R1# sh cry isakmp key

R1# sh crypto isakmp policy

R1# sh crypto is sa

R1#sh cry isakmp peers

R1#sh crypto ipsec transform-set

R1#sh cry ipsec sa

R3 will have identical mirror config.

LAB 2: SITE-to-SITE vpn ikev2

Step to create ikev2 site-to-site vpn:

Step 1: ikev2 proposal (encryption, integrity and DH group)

Step 2: create ikev2 policy (call proposal)

Step 3: Create ikev2 key ring (peer name, address and local and remote pre-share key)

Step 4: create ikev2 profile (match local and remote identity, local and remote authentication method, call key-ring)

Step 5: create IPsec transform-set

Step 6: ACL for interesting traffic

Step 7: create crypto map (transform-set, profile, peer, DH group, ACL)

Step 8: Apply crypto map to wan

Step 9: create tunnel interface

R1#

crypto ikev2 proposal Pro1

encryption aes-cbc-128

integrity md5

group 2

crypto ikev2 policy Policy1

proposal Pro1

crypto ikev2 keyring K-Ring

peer R3

address 192.168.2.2

pre-shared-key local cisco123

pre-shared-key remote cisco123

crypto ikev2 profile Profile1

match identity remote address 192.168.2.2 255.255.255.255

identity local address 192.168.1.1

authentication remote pre-share

authentication local pre-share

keyring local K-Ring

crypto ipsec transform-set TSET esp-3des esp-md5-hmac

mode tunnel

ip access-list extended GRE

permit ip any any

crypto map CMAP 1 ipsec-isakmp

set peer 192.168.2.2

set transform-set TSET

set pfs group2

set ikev2-profile Profile1

match address GRE

crypto map CMAP

interface Tunnel0

ip address 172.16.1.1 255.255.255.0

tunnel source Ethernet1/1

tunnel destination 192.168.2.2

tunnel mode gre ip

nterface Ethernet1/1

ip address 192.168.1.1 255.255.255.0

ip mtu 1400

ip tcp adjust-mss 1360

duplex full

crypto map CMAP

end

debug crypto ikev2 packet

debug crypto ikev2 internal

show crypto ikev2 sa detailed

show crypto ipsec sa

show crypto session

R1#sh cry ikev2 sa

R1#sh crypto ikev2 session

LAB 3: DMVPN with IKEv1

Step to create ikev1 DMVPN tunnel:

1. Crypto pre-share key

2. Crypto isakmp policy (authentication , encryption, hash and DH group)

3. Transform set

4. Profile (transform set)

5. ACL for interesting traffic

6. Crypto MAP

7. Apply crypto map to wan interface.

R1-Configuration for Hub
!
crypto isamkp key cisco123 address 0.0.0.0 0.0.0.0
!
crypto isakmp policy 10
authentication pre-share
group 2

crypto ipsec transform-set TSET esp-aes esp-sha-hmac

Crypto ipsec profile MY_PROFILE
Set transform-set TSET
!

Interface tunnel 0
bandwidth 1000
no ip next-hop-self eigrp 1
no ip split-horizon eigrp 1
Ip address 172.16.1.1 255.255.255.0
ip mtu 1400
ip tcp adjust-mass 1360
Ip nhrp authentication cisco123
Ip nhrp map multicast dynamic
Ip nhrp network-id 5
tunnel source eth 1/1
tunne mode gre multipoint
tunne key key6
tunnel protection ipsec profile MY_PROFOLE

router eigrp 1
network 10.10.10.0 0.0.0.255
no auto-summary
exit

Configuration on spoke R2
!
crypto isakmp policy 10
authentication pre-share
group 2
!
crypto isakmp key cisco123 address 0.0.0.0 0.0.0.0
!
crypto ipsec transform-set TSET esp-aes esp-sha-hmac
!
crypto ipsec profile MY_PROFILE
Set transform-set TSET
!
interface tunnel 0
bandwidth 1000
ip add 172.16.1.2 255.25255.255.0
ip mtu 1400
ip tcp adjust-mass 1360
ip nhrp authentication cisco123
ip nhrp map multicast 192.168.1.1
ip nhrp nhs 172.16.1.1
ip nhrp map 192.168.1.1 172.16.1.1
ip nhrp network-id 5
tunnel source eth 1/1
tunnel mode gre multipoint
tunnel key 6

router eigrp 1
network 20.20.20.0 0.0.0.255

Note: R3 will have identical configuration as R1, with updated tunnel ip.

# Show ip nhrp deail

# show crypto ipsec sa

LAB 4: DMVPN with IKEv2

Steps for IKEv2 DMVPN:

1. IKEv2 proposal (define encryption, integrity, and group)

2. IKEv2 policy (attach proposal to policy)

3. IKEv2 keyring (peer, local and remote key)

4. IKEv2 profile (attach key ring)

5. IPsec profile (call ikev2 profile)

6. Create tunnel: apply ipsec profile using tunnel protection ipsec profile command

Topology:

R1 Hub Config

crypto ikev2 proposal ikev2-proposal

encryption aes-cbc-256

integrity sha512

group 15

crypto ikev2 policy ikev2-policy

proposal ikev2-proposal

crypto ikev2 keyring K-Ring

peer ANY

address 0.0.0.0 0.0.0.0

pre-shared-key cisco123

crypto ikev2 profile ikev2-profile

match identity remote address 0.0.0.0

authentication remote pre-share

authentication local pre-share

keyring local K-Ring

crypto ipsec profile ipsec-profile

set ikev2-profile ikev2-profile

interface Ethernet1/1

ip address 192.168.1.1 255.255.255.0

ip mtu 1400

ip tcp adjust-mss 1360

duplex full

end

interface Tunnel0

ip address 172.16.1.1 255.255.255.0

no ip redirects

ip nhrp authentication cisco123

ip nhrp map multicast dynamic

ip nhrp network-id 1

tunnel source Ethernet1/1

tunnel mode gre multipoint

tunnel protection ipsec profile ipsec-profile

end

R2 Spoke Config

crypto ikev2 proposal ikev2-proposal

encryption aes-cbc-256

integrity sha512

group 15

crypto ikev2 policy ikev2-policy

proposal ikev2-proposal

crypto ikev2 keyring K-Ring

peer ANY

address 0.0.0.0 0.0.0.0

pre-shared-key cisco123

crypto ikev2 profile ikev2-profile

match identity remote address 0.0.0.0

authentication remote pre-share

authentication local pre-share

keyring local K-Ring

crypto ipsec profile ipsec-profile

set identity ANY

set ikev2-profile ikev2-profile

interface Tunnel0

bandwidth 1000

ip address 172.16.1.2 255.255.255.0

no ip redirects

ip nhrp authentication cisco123

ip nhrp map multicast 192.168.1.1

ip nhrp map 172.16.1.1 192.168.1.1

ip nhrp network-id 1

ip nhrp nhs 172.16.1.1

tunnel source Ethernet1/1

tunnel mode gre multipoint

tunnel protection ipsec profile ipsec-profile

end

interface Ethernet1/1

ip address 192.168.1.2 255.255.255.0

ip mtu 1400

ip tcp adjust-mss 1360

duplex full

R2 #sh cry ikev2 session

R2#sh crypto ikev2 sa

2022-10-09T00:28:00.001+05:30

SDWAN

Traditional network:

Branch office connecting to central office (Headend / DC) using MPLS or DMVPN.
If there site is multi-home, it uses one of the path based on network reachability or policy configured.
Devices at each site are managed and configured separately

Limitation of traditional topology

Scaling over MPLS may be expensive.
With upcoming cloud technology and associated services (e.g. office 365, drop box, one note etc), we may require traffic going out to different location (like Microsoft Azure, Amazon AWS, Google cloud) apart from central office.
Qos can be issue on internet link.
Troubleshooting is not easy..

SD-WAN:

SDWAN changes Configurable network to programable network. So with this we don’t need to know how to configure devices from different vendor like cisco, juniper.
It divides network into two part, North bound and South bound.
North bound host all controller which can be used to manage SD-WAN eco system.
User can configure policy by on Controller by using API
Southbound (CPE) device are managed by north bound controller. Reduced manual configuration task.
Introduces application aware routing.

SDN terms:

APIs (Application programming interfaces) – simplifies network view for app developers.
Embedded programming language – e.g Python interpreter.
Network controller – simplifies writing source code for developer
ASIC firmware – provides access to lower-lever firmware
Application hosting – network devices with dedicated hardware to host apps
CMS (Configuration management software) - e.g Ansible, Chef, Puppet.
XMPP (Extensible management and presence protocol) - open source technology used for IM and presence

Separates Data plan , control plan and management plan.

CPU intensive task Control Plan and management plan is removed from router and move to central controller.
uses protocol like MP-BGP or OMPS (Overlay management protocol)

Cisco created iWAN (based on dmvpn), Cisco now brought Viptela (SD WAN vendor). We have other vendor like Versa

SD-WAN component

Cisco SD-WAN

vBond
Control Plane (vSmart)
Mgmt (vManage)
Data plane (vEDGE cEDGE)

Versa SD-WAN

Versa Director
Versa Controller
Versa Analytic
Edge CPE

Controller:

Support app aware routing policies, here it will monitor circuit and take decision to divert traffic over better link in case you have redundant circuit.
can take care of each individual app of office 365, e.g skype , email separately. It dig dipper for each application and route accordingly.
We can segment traffic like VRF.
We are also getting following product built in with SD-WAN

APP aware enterprise firewall
IPS
DNS layer enforcement with Umbrella
URL filtering.

All of above thing can be managed using vManage

Orchestrator ( vBond / Versa Director )

Acts like single pane of glass to manage system.

When we get new router for Branch office it should be able to reach vBond. Cisco vBond and Cisco vBond will redirect it to customer vBond router. Customer vBond will verify certificate and serial number.

Microsoft Azure

2021-12-17T16:13:00.007+05:30

Microsoft Azure cloud Networking components:

Azure terms used for networking component that my be useful for AZ-900 Foundation or administration exam.

vNet (Virtual Network):

It work like logical network boundary, represents supernet allocated for Azure resource group.
Under vNet we can create multiple subnet. Minimum one subnet is required to create vNet.
vNet exists with subscription and region and cannot span subscription or region. There is limit for vNet soft limit =50 and hard limit = 500.
Routing between subnet in vNet is automatic and enabled by default using System Routes. System route cannot be modified or deleted, but we ca override it using custom route.
Traffic from vNet to azure service is routed via Azure’s backbone network. Rest other traffic (except RFC 1918, RFC 6598) are routed via public internet

Route table.

Route table are used to route traffic between vNet or another network.
It contain 3 important information, source, destination and next-hop

Source = defines who created route (Default / system << Virtual Network Gateway / BGP << UDR (User defined route)
Destination : Subnet of destination network
Next-hop: 1st hop to reach destination network.

Most specific / longest prefix route is preferred, if there are multiple route to same destination than preference is (UDR >> Virtual Network Gateway >> System)
Next-hop type:

Virtual network gateway
Virtual network (default Azure routing)
Internet
Virtual appliance (specified VM)
None (black hole / drop traffic)

Network Security Group (NSG):

It acts like FW at network lever used to filter inbound / outbound traffic.
It is applied at VM (NIC) level or Subnet level.

Service endpoint:

Allows communication from vNet to Azure service (e.g. blob service)

Application Security Group (ASG)

Help to manage security of VM by grouping them according to the application that run on them. (e.g. Internet >>> webserver >>> app server >>> database server

Azure Firewall and Azure Firewall manager

Azure Firewall is firewall service from Azure and Azure Firewall manager is used to manage it.
Azure Firewall manager support secured virtual hub and hub virtual network.

Bastion host:

Node used as jump server, jump box or remote server host for client coming from internet.

NAT Gateay

Network address translator

Azure DNS

DNS service from Azure

Azure load balance.

Used to balance network traffic / session load between group of servers.
There are public (external) and private (internal) load balancer.

Application Gateway :

It works like L7 load balancer and can used path-based routing.

WAF (Web application Firewall)

Used to protect web application use along with Application gateway.

Azure traffic manager: a. Used as DR / HA solution to route traffic between different region.
Express route:

Dedicated 10Gig connectivity to Azure cloud using private network via express route provider.

VPN Gateway:

Allows to connect remote site (Site-to-Site) or user (Point-to-site) vpn

Local network gateway:

Network object that represent on-premises location, used while configure VPN gateway.

Virtual WAN

Form of HUB which allows to interconnect all vNet and on-premises site or remote user.

vNet peering:

allows routing traffic between two vNet using Microsoft backbone network infrastructure

Gateway transit:

Allows vpn hub to forward traffic from spoke

Azure FrontDoor:

Microsoft global edge network that acts like entry-point to access hosted resource (Azure / on-premises) from public internet.

Azure private link:

Allow access to Azure service using private address space.

Azure private link service.

Allows communication between resource from two vNet / network hosted in Azure using overlapping private ip

Python Concept - Script, Module, library, function and classes

2021-07-31T19:05:00.010+05:30

Important concept of Python 2021

Understanding Script, module, package, library

· Script: python file that run directly to perform certain task.

· Module: Python file that is imported in script or another program. It defines member like classes, functions and variable intended to be used in other files that import it.

· Python.org definition: An object that serves as an organizational unit of Python code. Modules have a namespace containing arbitrary Python objects. Modules are loaded into Python by the process of importing.

· Package: collection of related modules that work together to provide certain functionality. This are folder containing modules. It has special file with name __init__.py

· Python.org definition : A Python module which can contain submodules or recursively, subpackages. Technically, a package is a Python module with an __path__ attribute.

· To create Python package ourself, we have to create directory and a file named __init__.py inside it. This file cab be empty.

· Note: Directories without an __init__.py file are still treated as packages by Python. However, these won’t be regular packages, but something called namespace packages.

· In general, submodules and subpackages aren’t imported when you import a package. However, you can use __init__.py to include any or all submodules and subpackages if you want.

· Library: a bundle of code / collection of packages. E.g. Matplotlib (plotting libaray)

o Standard library (available by default)

o 3rd-Party Modules

Understanding import methods / option:

It is python keyword to make code in one module available in another. They help to structure code.

Method 1: Basic import:

Here pi is variable in math module.

Math acts as namespace (In computing, a namespace is a set of signs (names) that are used to identify and refer to objects of various kinds. )

To see content of math module you can use dir(math)

Method 2: import specific part (objects) from module

Method 3: import with rename

Importing module gives access to its objects using syntax: module.object

Method 4: Relative import.

From . import <sum-package-name>

The dot refers to the current package, and the statement is an example of a relative import. You can read it as “From the current package, import the subpackage <sum-package-name>”

Method 5 absolute import:

From math import pi

The PEP 8 style guide recommends using absolute imports in general. However, relative imports are an alternative for organizing package hierarchies. For more information, see Absolute vs Relative Imports in Python.

Don’t use from <module> import *

Python import path:

You can inspect Python’s import path by using sys.path.

List will contain three different kinds of locations:

· The directory of the current script / current directory

· The contents of the PYTHONPATH environment variable.

· Other, installation-dependent direcotires.

Note 1: clearing import catch

Modules are cached, if we update module then we need to re-import it in old session and delete old cache.

That can be done using

Reload(<module-name>)

For Python3 (its not available by default)

Import importlib

Importlib.reload(<module-name>)

Note 2: __main__

Sometimes we want code to be executed when module is run directly , but not when it is imported by another module.

If __name__ == ‘__main__’ allows us to check whether the module is being run directly.

Understanding function, class

Function is set of code that can be called repeatedly

What is Class ?

Object oriented programming (OOP):

OOP terms:

· Class

· object

Object has two parameters:

1. Attributes (data / properties e.g. age, name etc)

2. Behaviors (action walking, talking etc)

E.G. phone is object, but its design is class and object is instance.

Object is instance of class.

Function is OOP is called method.

· Class can be considered as template for creating object with related data (attributes) and function (action) that do interesting thing with that data.

· Class help to create customized data type

· Function inside the class is called method.

# Creating class Example 1

Class User:

Pass

Note: pass is a sort of place holder.

Creating object

# User1

User1=User()

# Creating class Example 2

To use instance variable inside class function we can use self.<instance-variable-name>

Creating class with variable Example #3

Class Router:
    ‘’’Router Class’’’
    def __init__(self,model,swversion,ip_add):
        ‘’’initialize values’’’
        self.mode=model
        self.swversion=swversion
        self.ip_add=ip_add

rtr1=Router(“ios”,”15.6.7”,”10.10.10.1”)

Function __init__ is called dunder or magic methods.

To store attributes we map the name self and the value you pass to it become variables inside the object, which is then store those value as attributes.

>>> rtr1.model

“ios”

We can define additional variable later.

>>> rtr1.desc =”virtual router”

>>> rtr1.desc

“virtual router”

Inheritance in Python classes allow a child class to take on attributes and methods of another class.

Class Switch(Router):

Here class Switch inherits the attribute of parent class Router.

Killing window application via python

Import os

os.system("taskkill /f /im notepad.exe")
os.system("taskkill /f /im winword.exe")
os.system("taskkill /f /im excel.exe")
os.system("taskkill /f /im powerpnt.exe")
os.system("taskkill /f /im outlook.exe")
os.system("taskkill /f /im chrome.exe")
os.system("taskkill /f /im calc.exe")
os.system("taskkill /f /im iexplore.exe")
os.system("taskkill /f /im powershell.exe")
os.system("taskkill /f /im wordpad.exe")

2020-12-25T11:08:00.010+05:30

Machine Learning

24 December 2020

Introduction:

Machine Learning: It part of computer science that gives computer to learn without being explicitly programmed. Process is same as how human learn and then use his knowledge in day to day work and inventing new things. Process allow machine to learn form historical data and predict something.

ML Application:

· E-commerce or entertainment site for predicting / recommending customers. E.g Netflix and Amazon can predict what their customer need and also recommend their customers.

· Build good decision-making tree or algorithm / application.

· Healthcare industry: to predict future health condition or develop medicine or treatment for particular health issue.

Statistical modeling used for ML

· Popular arithmetical algorithms: Regression, Classification, and Clustering
· Recommender Systems: Content-Based and Collaborative Filtering
· Popular models: Train/Test Split, Gradient Descent, and Mean Squared Error

ML techniques:

·   Regression / estimation technique: used to predict continuous value.
·         Classification technique – used for predicting class or category of a cases.
·         Clustering – grouping of similar cases.
·         Association technique -used to find events or items that often co-occur.
·         Anomaly detection – discover abnormal or unusual case or behavior.
·         Sequence mining – used to predict next event.
·         Dimension reduction – used to reduce size of data
·         Recommendation system -recommend customer for particular product or item.

Difference between AI / ML / DL

AI(Artificial Intelligence)- make computer intelligent to perform function normally done by human. AI includes Computer Vision, Language Processing, Creative and summarization.
ML(Machine Learning)- is branch of AI that works with statistical part of AI. It helps computer to solve problem.
DL(Deep Learning)- this is enhancement of ML where computer learn and make decision.
DS: Data Science

Objective of Machine Learning (ML):

In machine learning we create models, that can be used for predication or processing.

IBM cognitiveclass.ai/ courses recommends:

· Python packages, Numpy, SciPy, Matplotlib, Pandas Library and Scikit-learn

Open Source AI using Scikit-learn: (Source- IBM Cognitive Class)

· It is a free ML library for the Python programming language.

· It has built in algorithm or ML techniques.

· Has good documentation and used with few line of python code.

· Most task required for ML are implemented already in Sci-kit learn. So easy to implement.

How to use Scikit-learn:

· It uses standardized data set, we can take any non-standard data and fix them.

· You have to split your dataset into train and test sets to train your model. And then test the model’s accuracy separately

· Normal recommendation

o 70 – 80 % data used as Train Set

o 10 – 20 % validation Set

o 10 – 20 % Test set

· We setup algorithm and train your model with the train set. Outcome is to get unknow value.

· We can use different metrics to evaluate your model accuracy.

· Finally save your model.

The Microsoft Cloud-powered AI Platform:

· Azure AI Services:

o Cognitive Services (Pre-built AI)

o Azure ML services (Custom AI)

o Bot Services (Conversation AI)

· Azure Infrastructure:

o Database, CPU, GPU etc.

· Tools:

o Coding & Management Tools:

§ Azure ML for VS code

§ Drag & Drop Designer

§ Automated ML

o Deep Learning Frameworks

§ Cognitive toolkit

§ Tensor Flow

§ Caffe

Microsoft Pre-Built AI Services.

· Vision : API for gesture

o Computer Vision

o Ink Recognizer

o Face

o Video Indexer

o Custom Vision

o Form Recognizer

· Speech

o Speech Translation

o Speaker Recognition

o Speech to Text

o Text to Speech

· Language

o Immersive Reader

o Translator text

o Language understanding

o Text Analytics

· Search

· Decision

We can download Intelligent Kiosk from Microsoft Store

Azure portal: portal.azure.com/#home

Type of learning model:

Supervised:
Unsupervised
Semi-Supervised

Supervised:

we teach mode or load model with knowledge so that we can have it predict future instance. We teach model by using some data from labeled dataset.

Sample: Labeled Data

Type of supervised learning:

Classification: it is process of predicting a discrete class label or category

Decision Trees:

Two-Class Classification. Example True / False, Yes / No

Multi-Class Classification

Regression: is the process of predicting a continuous value.

Regression Wiki:

In statistical modeling, regression analysis is a set of statistical processes for estimating the relationships between a dependent variable (often called the 'outcome variable') and one or more independent variables (often called 'predictors', 'covariates', or 'features').

The most common form of regression analysis is linear regression, in which a researcher finds the line (or a more complex linear combination) that most closely fits the data according to a specific mathematical criterion.

Unsupervised Learning:

We don’t provide training to model but allow model to learn or discover of its own. It can work on unlabeled data. It is using more complicated algorithm then supervised learning.

Technique used by unsupervised learning.

·         Dimension reduction
·         Density estimation
·         Market basket analysis
·         Clustering

K Means

Challenges and Risks Bias can affect result(Source Microsoft AI classroom course)

·         Errors may cause harms
·         Data could be exposed
·         Solution may not work for everyone
·         User must trust a complex system
·         Who’s liable for AI Driven Decisions

Principles of Responsible AI (Source Microsoft AI classroom course)

·         Fairness
·         Reliability and safety
·         Privacy and security
·         Inclusiveness
·         Transparency
·         Accountability

Cisco DevNet

2020-06-02T22:36:00.001+05:30

Software development methodology:
Waterfall / Agile / Lean

1: Waterfall Methodology:

It is a linear project management approach, where customer requirements are gathered at the beginning of the project, and then a sequential project plan is created to accommodate those requirements.

{Requirements -- Design -- Implementation -- Verification --- Final Release -- Customer Feedback }

2: Agile Methodology:

Here there is continuous iteration of development and testing throughout the software development lifecycle of the project

{Requirements -- Design -- Implementation -- Verification --- Intermittent Release -- Customer Feedback } Cycle repeat multiple time till project end.

3: Lean Methodology:

It’s like updated version of Agile by promoting the flow of value to the customer through two pillar: continuous improvement and respect for people.

{Requirements -- Design -- Implementation -- Verification --- Intermittent Release -- Customer Feedback -- Continuous service improvement } Cycle repeat multiple time till project end.

Software Architecture design pattern.

What is MVC ?

Model View Controller

MVC is one of the most frequently used software architecture design pattern.

It separates application functionality and promotes organized programming.

Role:

Controller : Handles request flow only

Model : handles data logic, interact with database

View : handles data presentation

Flow
1: Client send Request to Controller
2: Controller communicate with model get data from model,
3: Controller communicate with View to get presentation
4: controller send respond to client

GIT: (Version control system)

It is repository that provides Distributed Version Control System (DVCS) for tracking changes in computer files.

It helps to co-ordinate work between multiple developer

Benefit of Git.

keeps track of code history

takes snapshots of files so that we can revert back at any time

We can stage file before committing

Installing GIT

Debian Linux : $ sudo apt-get install git

Fedora Linux : sudo yum install git

For Mac and Window : download from http://git-sc.com/download

Basic Git commnads

$ git init // initialize local git repository

$ git add // add files to index

$ git status // check status of working tree

$ git comit // comit changes in index

$ git push // push to remote repository

$ git pull // Pull latest from remote repository

$ git clone // clone repository into a new directory

$ git --version // shows git version

SCM

Software configuration management

Source code management

Updating In-progress: #############

Hypervisors:

VMware vSphere : all component together makes VMware's enterprise virtualization platform

VMware hypervisor / ESXi 5 - Hypervisor Operating System that run on the physical server. This is basic package which is installed on hardware and make possible virtualization.

ESXI is also called as host

What is hypervisor ?
A software layer or OS which presents hardware to the Guest OS.

Types of hypervisor

Type 1 : bare Metal : in this case hypervisor run directly on hardware

Type 2 "hosted": in this case hypervisor runs as application service on top of traditional OS, hardware is presented by host OS (window or Linux)

VMware ESX 3.5 boots red hat and then hypervisor
ESXi - things are changed
***************************************

Virtual machine : a container which is capable of installing and or running an operating system

*****************************************************

Guest : an OS running on a hypervisor within a Virtual Machine container

***************************************
Cos : console OS which is responsible for providing a user interface on the server itself

Cos in window is shell called explore.exe and in Linux it is bash

vCenter 5 - Service that Manges ESXi host (vcenter server is services runs on server end)

vSphere client - client to connect and configure vcenter and ESXI hosts.

Running desktop os on VM is expensive so we have

other comment :
vSphere desktop and VMware View (low license cost vm to host desktop os)
VMWare workstation ( run VM on desktop)

Other vendor
Citrix : Citrix XenServer
Microsoft Hyper -V

What is Docker ?

Normal application development process.

Developer develop application > send for testing > operation team install it on Server.

While developing we require framework, dependence or libraries when software is sent for testing, testing machine may not have similar framework, dependence or libraries. So, it might lead to failed while testing.

One of solution is to use Hypervisor, so now development team will not only send software for testing, but they will send image (Guest os + software) to tester. But this will create problem while sending it to operation team, operation team now will have to use one image for each software this will cause wastage of resources and license.

Now if we use docker which create container, we have advantage it can work like client, it can work as server or it can be shared socially.

What is a Docker Container?

A Docker container is an open source software development platform. Its main advantage is to package applications in containers, allowing them to be portable to any system running a any operating system. A Windows machine can run Linux containers by using a virtual machine (VM). Docker is only one form of container technology.

Docker Containers:

It is virtualization techn. VMs, also just one form of virtualization, allow a piece of hardware to host multiple operating systems as software. VMs are added to the host machine so that the hardware power can be shared among different users and appear as separate servers or machines. Containers virtualize the OS, splitting it into virtualized compartments to run container applications.

The Docker daemon does the assembling and running of code as well as the distribution of the finalized containers. It takes the commands from developer and enters into the Docker client terminal and executes them.

This allows pieces of code to be put into smaller, easily transportable pieces that can run anywhere Linux or Windows is running. This way we make applications more distributed, and strip them down into specific functions.

Automation of software delivery using CI / CD

Earline we were using Waterfall model: client request for project, team work on project and after project is completed it was delivered to client.

To make think better we are now we are using Agile: we give client part /pipe of product 2-3 week and ask for feedback.

If project is divided into multiple module and developed by multiple developer.

All developer will test their module, but since all this module work together, we need integration testing.

All developer needs to integrating testing, if we get problem during testing, we have CI continuous integration.

Every day or every time developer will commit and tested using CI.

So, moment we done code and working in unit test we commit it so that integration test can be done.

2^nd part is CD (continuous deliver and continuous deployment)

In continuous deliver we show demo of project to client on Mock Server.

So, in integration is we are pushing code for integration testing and delivery we are making it available for deployment

What is continuous deployment?

Her we directly deploy project without deliver, here there is risk if something goes wrong.

Data Formats and Data Models

Like network device required protocol to communicate among themselves, application too need agree on some standard data format and structure to exchange data among them

A data model is an abstract model that organizes elements of data and standardizes how they relate to one another and to the properties of real-world entities. (As per Wikipedia)
Example: JSON, XML

A data format is the arrangement of data fields for a specific shape
Example: YANG
Data models define how the data stored in a particular data format is structured.

Following example represent temperature and humidity of city in country:

1: Using XML Format:

2: Using JSON (Java Script Object Notation)

Jason data is written as key value pair separated by colon, here temp and humidity are keys and 37 and 40 are corresponding values. Each data is separated by coma accept last one and enclosed in curly braces. Key string has double quote, for value if its number no double quote is used.

{

“country”;

{“city”;

{

”temp”:37,

”humidity”:40

}

YAML

YAML is data serialization language used to store information about different object
We can use yaml to define key value pair, variable list and object
It is similar to JASON. It uses file extension .yml and .yaml
For comment we use #

Example define information about person

Person:

Name: “Rama”

Occupations: “Developer”

Age: 30

Fav_num: 2e+10

Male: Ture

Birthday: 1990-01-01 14:40:22 iso 8601

Flaw: null

Indentation is important
To access value use person.name
Apart from key value object we can also define list
Hobbies:
-hiking

- Movies

- riding bike

Another way to define list

Movies: [“oh my god”, “goal”]

Defining object

Friends:

-name: “Hanuman”

- Age:30

Another way to define list

-{name:”Bharat”,age:22}

Another way to define list

Name: ”Laxman”

Age:23

Storing large about of data : E.G description

Description:

Hi this program

Is to learn in yaml

Description :> # > make store data in single line

Signature: | # | ask yaml to preserve

Abcd
Xyz inc
Email – abcd@xyz.com

Anchor data in YAML, image we want to create another variable id and this should be same as name

Name: &name “Mike” # if we change name id will also change

Id:*name

Anchor key value pair

Base:& base
Var1: value 1

Foo:

<<: base="" nbsp="" o:p="" var1:value1="">

Different data type converted to other type

Age:!!float 23 # covert 23 to s3.0

Gpa:!!str 3.5 # will change #3.5 to “3.5”

REST API

What is API ?

Application Programming Interface, which allow one piece of software talk to another.

There are different types of API, One of them is REST API.
REST: REpresentational State Transfer

REST work same like http

REST give states of an object,
e.g. we can send request to get temperature and humidity of specific location / place.

Here place is object and temperature and humidity data is state.

Soap is legacy method , now everyone uses REST

Rest call flow:

Client à http call to à Server

CRUD : Four basic functions of persistent storage.

Create

Read

Update

Delete

Corresponding http method
Create   ---    Post
Read     ---    Get
Update ---    Put
Delete   ---    Delete

We get response back with Java script object notation (JASON) formatted data, it is structured data with key value pair.

We can get data in XML or JASON

HTTP Request methods

GET – get data from API

POST – Post data in body of request

Difference between REST and SOAP

               REST                                                                          SOAP
Representational State Transfer                             Simple object access protocol
Communicate over http uses http verbs                  Communicate over http, smtp, tcp, udp
Return data in different format as per request       Uses XML for its message format.

Rest request uses URI

REST Code:
200    OK
400    Invalid Request
401    Authentication failure
403    Access is not allowed
500    Something went wrong on the server
503    Server is overloaded

One of REST client is POSTMAN

Postman

It is API Client, it help to develop, test, share and documents APIs

Postman is the only complete API development environment. The comprehensive set of built-in tools support every stage of the API lifecycle so individuals and teams can easily maintain a single source of truth. You can design and mock, debug, test, document, monitor, and publish your APIs from the Postman UI.

https://getpostman.com

NETCONF:

We can configure router using different method

· cli (using telent / ssh)

· SNMP (using NMS )

· NETCONF (NETworkCONFiguration)

Why we need netconf?

Using traditional CLI config we need to enter command per line on each device for doing network changes. SNMP option can automate it but its not scalable.

In today’s network we want to have application with deeper integration with network and DEVOPS allowed develop and deliver software to network devices not just by network engineer but also Developers.

Benefit / Feature of Netconf:

· Allows to configure network device using program instead of cli and enter individual command.

· It is IETF standard introduced in 2006

· Intent based networking: Netconf is not vendor dependent, work with multiple vendor.

Netconf component :

Like client-server architecture where have Client requesting data from server. Netconf we have Manager and Agent.

· Manager (may have some application e.g python app)

· Agent (network devise such as switch or router)

It uses YANG data model, yang data is encoded in XML format and transported using netconf.

{Netconf[XML(YANG DATA)]}

Netconf uses secure shell, we have utility like ncclient

Yang (Yet Another Next Generation):

Yang data model are created by different vendor, it may be by IETF or Hardware Vendor.

Module name in yang data tell who created module

Yang data model of a network interface: module à container à list

Yang was standardized in 2010,

Netconf use xml data format to encapsulate YANG data

Overview of Cisco Tool for Network Automation:

DNA (Digital Network Architecture) Solution:

DNA Center (is controller for DNA)

SD-WAN or enterprise network or campus use

DNA-Center is evaluation of EPIC-EM

One of component of DAN center is Assurance. Which check health of the network.

Data plan don't go through controller. Only management / reporting plane is moved to controller. Routing and forwarding decision is taken at network edge level.

Southbound in DNA center has devices which DNA center manages. CLI, NETCONF, RESTAPI. Northbound it connect to thing which manages DNA, e.g. RESTAPI

ACI (Application Centric Infrastructure:

ACI solution is designed for DC environment.

In DC we need high speed connectivity like 10 Gig / 40 Gig or may be 100 Gig in future. To support this we use Nexus switch.

We can say Nexus switch = High speed LAN switch + FC SAN Switch

To manage DC Nexus switch we can use ACI. We also open source controller to manage nexus instead of ACI.

PUPET open DEVOPS configuration management tool. Used for Server and application component. Nexus product has agent for PUPET, CHEF etc.

NSO (network service orchestration ):

Originally targeted for service provider to configure large scale environment. It's not controller like ACI or SDN but it is used as configuration management tool.

VMware, ESXI, Virtual machine overview

2019-12-31T12:49:00.002+05:30

VMware vSphere : all component together makes VMware's enterprise virtualization platform

****************************************
VMware hypervisor / ESXi 5 - Hypervisor Operating System that run on the physical server. This is basic package which is installed on hardware and make possible virtualization.

ESXI is also called as host

What is hypervisor ?

A software layer or OS which presents hardware to the Guest OS.

Types of hypervisor
Type 2 "hosted": in this case hypervisor runs as application service on top of traditional os, hardware is presented by host OS (window or linux)

Type 1 : bare Metal : in this case hypervisor run directly on hardware

VMware ESX 3.5 boots redhat and then hypervisor
ESXi - things are changed
***************************************

Virtual machine : a container which is capable of installing and or running an operating system

*****************************************************

Guest : an OS running on a hypervisor within a Virtual Machine container

***************************************
Cos : console OS which is responsible for providing a user interface on the server itself

Cos in window is shell called explore.exe and in Linux it is bash

vCenter 5 - Service that Manges ESXi host (vcenter server is services runs on server end)

vSphere client - client to connect and configure vcenter and ESXI hosts.

**********************************************************

Running desktop os on VM is expensive so we have

other comment :
vSphere desktop and VMware View (low license cost vm to host desktop os)
VMWare workstation ( run VM on desktop)

other vendor

Citrix : Citrix XenServer
Microsoft Hyper -V

******************************

AI ML DL DS

2019-12-31T12:38:00.001+05:30

· AI: Artificial Intelligence

· ML: Machine Learning

· DL: Deep Learning

· DS: Data Science.

· AI: enable machine to think. That means without any human intervention machine will take decision.

o E.g Driverless CAR

· ML: Machine learning is subset of AI, provide statistical tools to explore and analyze the data

o There are 3 different approaches

ü Supervised

ü Un-supervised

ü Reinforcement learning / semi supervised ML

o Supervised: we will have data in hand to be processed, past labeled data and we know what will be output of data

o Un-supervised: we don’t have data, we solve clustering problem. Clustering mean based on similarity of data it will try to group data together. We have 3 different algorithm K Means clustering, db scan clustering, Hierarchical clustering

o Reinforcement learning / semi supervised ML: Some part of data will be labeled, and some will not be learned, in this model computer learn slowly using past data and new data

· Deep Learning: Multineural network architecture, make machine to learn like human.

o ANN : Artificial neural network , if data is in form of number we use ANN

o CNN : Convolutional neural network , if data is in form of images we use CNN

o TL (Advanced Neural network based on CNN)

o RNN : Recurrent neural network , if our data is in form of time series data

· Data Science: use all above technique and use mathematical tool like statistic, probability and linear analyses

Expanding exiting 3650 stack.

2018-08-24T15:08:00.001+05:30

Following document explain procedure to expand existing 3650 stack.

#############################################################

Pre-deployment activity:

1 Backup configuration of existing stack.

2 Verify existing stack status using.

show switch : Ensure all switches are in ready state and have appropriate priority set.
show inventory
show version
show run | inc provision

3. Identify the number < Switch Number> which should be given to switch that will be added in existing stack.

4. Provision new switch on existing stack using configuration command.

Switch < Switch Number> provision
Verify status using – ensure new switch is in provisioned state
Save the configuration.

5. Ensure auto-upgrade is enabled on existing stack ( global configuration command)

software auto-upgrade enable

6. On new switch, in case old switch is re-used erase the configuration.

7. By default switch will number to 1 / switch 1. Renumber this switch to new number.

Switch 1 renumber < Switch Number>
Reload the switch.

8. After reboot verify switch configuration / setting.

Show switch

9. Provision switch 1 on new switch.

10. Stack new switch

11. Power on stack ( it might take 15 – 20 minute for new switch become member of existing stack.

12. Verify stack.

13. Set stack priority for new member in stack.

14. Save the configuration.

Python

2018-08-24T14:48:00.001+05:30

Introduction to Python :

Python is a high-level, interpreted, interactive and object-oriented scripting language.

· Python is Interpreted: Python is processed at runtime by the interpreter.
You do not need to compile your program before executing it. This is similar to PERL and PHP.

· Python is Interactive: You can actually sit at a Python prompt and interact with the
interpreter directly to write your programs.

· Python is Object-Oriented: Python supports Object-Oriented style or technique
of programming that encapsulates code within objects.

· Python is a Beginner's Language: Python is a great language for the
beginner-level programmers and supports the development of a wide range of applications
from simple text processing to W W W browsers to games.

History of Python:

Python was developed by Guido van Rossum in the late 80s and early 90s at the National Research Institute for Mathematics and Computer Science in the Netherlands.

Python is derived from many other languages, including ABC, Modula-3, C, C++, Algol-68, SmallTalk, and Unix shell and other scripting languages.

Python is copyrighted. Like Perl, Python source code is now available under the GNU General Public License (GPL).

Python is now maintained by a core development team at the institute, although Guido van Rossum still holds a vital role in directing its progress.

Python Features

Python's features include:

· Easy-to-learn: Python has few keywords, simple structure, and a clearly defined syntax. This allows the student to pick up the language quickly.

· Easy-to-read: Python code is more clearly defined and visible to the eyes.

· Easy-to-maintain: Python's source code is fairly easy-to-maintain.

· A broad standard library: Python's bulk of the library is very portable and cross-platform compatible on UNIX, Windows, and Macintosh.

· Interactive Mode:Python has support for an interactive mode which allows interactive testing and debugging of snippets of code.

· Portable: Python can run on a wide variety of hardware platforms and has the same interface on all platforms.

· Extendable: You can add low-level modules to the Python interpreter. These modules enable programmers to add to or customize their tools to be more efficient.

· Databases: Python provides interfaces to all major commercial databases.

· GUI Programming: Python supports GUI applications that can be created and ported to many system calls, libraries and windows systems, such as Windows MFC, Macintosh, and the X Window system of Unix.

· Scalable: Python provides a better structure and support for large programs than shell scripting.

Apart from the above-mentioned features, Python has a big list of good features, few are listed below:

· It supports functional and structured programming methods as well as OOP.

· It can be used as a scripting language or can be compiled to byte-code for building large applications.

· It provides very high-level dynamic data types and supports dynamic type checking.

· IT supports automatic garbage collection.

· It can be easily integrated with C, C++, COM, ActiveX, CORBA, and Java.

#################### Method to execute Python Code ######################

Interactive mode:

>>> print "Hello, Python!"; ßsyntex for 2.7

Scripted mode:

Open notepad , type following command and save it with .py extension .

print "Hello, Python!";

python test.py

$ chmod +x test.py # This is to make file executable

$./test.py

######################### Installation ################################

Installation of Python:

For windows

X 64 version for 64 bit OS

X 86 version for 32 bit OS

Document comes with CHM (compiled HTML)

Python - V to verify version of python

########################## Vocabulary #############################

Python program flow

· Program à module(s) ----- std library / import (top level py file)

· Modules à statements ----- statement is reserved key word

· Statements à expression --- expression is mathematical that operate on data

· Expressions à objects --- anything can be object, data entity

Modules

· Modules are functions and variables defined in separate files

· Items are imported using from or import

from module import function

function()

import module

module.function()

· Modules are namespaces

o Can be used to organize variable names, i.e.

atom.position = atom.position - molecule.position

Python is: (based on different type of data)

· Dynamically typed (e.g we don’t have to declare type for variable )

· Strongly typed

################ Python Identifiers #############################

· A Python identifier is a name used to identify a variable, function, class, module, or other object.

· An identifier starts with a letter A to Z or a to z, or an underscore (_) followed by zero or more letters, underscores and digits (0 to 9).

· Python does not allow punctuation characters such as @, $, and % within identifiers.

· Python is a case sensitive programming language. Thus, Manpower and manpower are two different identifiers in Python.

Here are naming conventions for Python identifiers:

· Class names start with an uppercase letter. All other identifiers start with a lowercase letter.

· Starting an identifier with a single leading underscore indicates that the identifier is private

· Starting an identifier with two leading underscores indicates a strongly private identifier.

· If the identifier also ends with two trailing underscores, the identifier is a language-defined special name

############### Lines and Indentation #############################

Blocks of code are denoted by line indentation, no braces used.

The number of spaces in the indentation is variable, but all statements within the block must be indented the same amount.

E.g

if True:

print "True"

else:

print "False"

### Above statement is correct, but bellow statement give error ######

if True:

print "Answer"

print "True"

else:

print "Answer"

print "False"

################### Python Keywords #############################

The following list shows the Python keywords. These are reserved words and you cannot use them as constant or variable or any other identifier names. All the Python keywords contain lowercase letters only.

And Assert	exec finally	Not or
Break	for	pass
Class	from	print
Continue	global	raise
def	if	return
del	import	try
elif	in	while
else	is	with
except	lambda	yield

########################## DATA TYPES ###########################

Immutable date (Fixed data type)

· Number

o Int

o Float

· String

· Tuple (“Sunday”,”Monday”, 123, “mango”)

Mutable data type (that can be changed or modified)

· List [ “Sunday”, “Monday, 123 ]

· Dictionary { 1:”Sunday”, 2: “Monday” } contain key:value pair

· file

Verify data time using type() function

isinstance() --- test for data type (Boolean)

################# Python Strings ################################

· Strings in Python are identified as a contiguous set of characters represented in the quotation marks.

· Python allows for either pairs of single or double quotes.

· Subsets of strings can be taken using the slice operator ([ ] and [:] ) with indexes starting at 0 in the beginning of the string and working their way from -1 at the end.

· The plus (+) sign is the string concatenation operator and the asterisk (*) is the repetition operator. For example:

PYTHON 2 uses ASCII character only 128 values using 7 bit

PYTHON 3 uses UTF-8 (1 – 4 byte)

str = 'Hello World!'

print str # Prints complete string

print str[0] # Prints first character of the string

print str[2:5] # Prints characters starting from 3rd to 5th

print str[2:] # Prints string starting from 3rd character

print str * 2 # Prints string two times

print str + "TEST" # Prints concatenated string

String operation :

Name = “myname”

Len(name) --- gives character length

+ --- concatenation

‘ * ‘ ---- repetition

str(name) ---- type casting, changing identity of data type

String slicing:

String method

Object.find()

Name.split() cuts string @ delimiter

Find location (position) of letter / character in string

Raw string prevent escape sequence interruption

Verify if particular sub-string exist in string

Syntax: “text” not in (variable) returns True / False

Syntax: “text” in returns True / False

Join()

To verify if string consist of alphabet or digit..

Isalpha()

Isdigit()

Byte class provides an immutable sequence. Value must be integers from 0 – 255 to represent a byte.

Byte array class provide an mutable sequence.

######################## Tuples #####################################

Tuples ()

· order set of data

· used for storing static program data

· Read only data

· Can be integrated with dictionary

· Immutable

· Slicing in tuple

Empty tuple e.g tup1 = ()

Single entry tuple e.g tup2 = (1,) , is necessary for single entry.

“a” in tup1

“a” not in tup1

Range

# set class provide a mapping of unique immutable elements

Exercise.

######################## List #######################################

List [ ]

· Can be modified or updated.

List operation :

Append() à add 1 element at the end

Count() à

Extend() à extend list

Index()

Insert () à insert element

Pop() à remove last element and returns the value, we can use pop using index to remove specific element.

Remove(0) à remove element using value, instead of index used in pop

Clear () à remove all element

Min()

Max()

Sorted() à only shows list in sorted

Sort() à will change original string

Reverse() à reverse the order

Dictionary

{key:value}

To retrieve information from dictionary.

.keys()

.values()

.items()

Pop() -- must provide value / key

In dictionary array is associated with hash table and don’t have order, so splicing don’t’ work.

###################### Operator ################################

‘ + ‘ add

‘ – ‘ subtract

‘ * ‘ multiply

‘ / ‘ divide

// quotient

% reminder

** power e.g 2**4 means 2^4

Comparison < , > , == , !=

Boolean : AND , OR , NOT

Order of operation (PEMDAS)

Parenthesis – exponential – Multiplication – Division – Addition – Subtraction

For more complex maths we can use standard library

1. fraction

2. math

external module : mum py & sci py

######################## Date & Time: ################################

>>> Import datetime

To display today’s date and time:

>>> datetime.datetime.today()

To display only date

>>> datetime.date.today()

Changing date in DD MM YYYY format

Where d à Day, b à Month, y à Year

#### File handling ###

CSV , comma separated value

Open file

F = open (“file_name”, “x”)

X = r (read only)

= a (append)

= w (write)

= r+ R/W

File opened using above method should always be closed manually. Using command

f.close()

In case we forgot to close the file, it will remain open.

So to avoid mistake / issue we should open file with context manage

So above command open file with context manage and content is stored in f_contents

f.readline() -- read line by line from 1^st to end

to go back to start use

f.seek(0)

##### copy one file to another file #####

############# Public and Private Data ######################

· In Python anything with two leading underscores is private

__a, __my_variable

· Anything with one leading underscore is semiprivate, and you should feel guilty accessing this data directly.

· Sometimes useful as an intermediate step to making data private

####################### Turtle ###################################

Import turtle

Turtle.Forward(25) -move forward by 25

Turtle.backward(30)

Turtle.left(30) - rotate left by 30 degree

Turtle.right(30) - rotate right by 30 degree

Turtle.shape(“turtle”) - changes cursor from triangle to turtle shape

Turtle.exitonclic() - close turtle window on click

Turtle.color(“red”)

To user RGB format for color

Turtle.colormode(255)

Turtle.color(215,100,170) for pink color

Help(turtle.color)

Turtle.width() change width of turtle cursor

turtle.reset() clears the screen

turtle.undo()

turtle.circle(10) where value 10 represent radius

turtle.penup() no lines – like pen not touching paper

turtle.pendonw()

turtle.title("welcome") change name of turtle window

input box inside turtle

>>> title = "input your data"

>>> promt = " what is your name ?"

>>> turtle.textinput(title,promt)

'Santosh'

Networking, Security & Cloud

Versa SD-WAN Command line quick reference.

Section 1: Console

# To switch from Shell to cli

# To switch from Cli to shell

Section 2: Getting System Details

CMD 2.1: To Get LSB release information (LSB = Linux Standard Base and Distribution information.)

CMD 2.2: To Get Serial, model and Software version.

CMD 2.2 To get only Serial and model number.

Section 3: Interface Command.

CMD 3.1: Get interface detail information.

CMD3.2.1 Get SFP information.

CMD 3.3 Interface utilization

CMD: Enable interface via cli.

Section 4: Configuring interface, enable interface.

Cisco Hardware refresh model recommendations

Cisco Hardware Refresh Jun 2025

Acces switches

Cisco catalyst 9200 switch characteristic:

Catalyst 9300

Catalyst 9400

Core switches

Features 9500

Features 9600

Wireless Controller

WLC 9800 WLC Feature

Branch WAN Router

WAN aggregation Router

Catalyst 8500 and 8500L series switches

Virtual Router

Ubuntu

Linux : Ubuntu

While installing Ubuntu you get 3 options:

Manual partitioning:

Cisco Nexus Switch CLI Cheat Sheet

Running Several Command on Single line.

Nexus# Conf t; int eth 1/1; no switch port; no shut

Roll back config change using checkpoint.

Create Checkpoint: Nexus# checkpoint <Check-Point-Name>Verify Checkpoint: Nexus# show checkpoint summaryCompare Config: Nexus # show diff rollback-path checkpoint <Check-Point-Name> running-configRollback Config: Nexus# rollback running-config checkpoing <Check-Point-Name>

Filter Command Ouput.

Nexus# show ip int brief | grep -i vlanNexus# show clock | ex NTP

Working with VRF

routing-context vrf <VRF-NAME>Show ip routerouting-context vrf default

Terminal color

Nexus# terminal color

alias

Nexus(config)# cli alias name <ALIAS-NAME> <Command>

Verify accounting log

Nexus# show accounting log | last 10

Wireless Networking Cheat Sheet

Wireless Networking Cheat Sheet

Wireless Standards

Common Wireless Terms

Wireless Security Protocols

Wireless Configuration Commands (Windows)

Wireless Troubleshooting Commands

Common Wireless Issues

Best Practices for Wireless Networking

Windows Command for Network Engineer

Wireless Networking Cheat Sheet

Wireless Standards

Common Wireless Terms

Wireless Security Protocols

- WEP: Wired Equivalent Privacy, outdated and insecure. - WPA: Wi-Fi Protected Access, improved security over WEP. - WPA2: Enhanced security, uses AES encryption. - WPA3: Latest security protocol, offers stronger encryption and protection against brute-force attacks.

Wireless Configuration Commands (Windows)

- Show available Wi-Fi networks: netsh wlan show networks - Connect to a Wi-Fi network: netsh wlan connect name="" - Disconnect from a Wi-Fi network: netsh wlan disconnect

Wireless Troubleshooting Commands

- Ping the access point: ping - Check signal strength: netsh wlan show interfaces - View wireless network properties: netsh wlan show profile "" key=clear

Common Wireless Issues

- Weak signal: Check distance from the access point, obstacles, and interference. - Connection drops: Update drivers, check for interference, and signal strength. - No internet access: Verify DHCP settings, check ISP connection, and router status.

Best Practices for Wireless Networking

- Use WPA3 for better security. - Select less crowded channels (1, 6, 11 in 2.4 GHz). - Position access points centrally to optimize coverage. - Limit SSID broadcasting for sensitive networks. - Regularly update firmware on access points and routers.

Windows Command Cheat Sheet for Network Engineers

Basic Networking Commands

Network Diagnostics

Network Share and File Commands

Firewall Configuration

Wi-Fi Commands

Network Adapter Management

Viewing and Managing Services

Create Checkpoint: Nexus# checkpoint <Check-Point-Name>
Verify Checkpoint: Nexus# show checkpoint summary
Compare Config: Nexus # show diff rollback-path checkpoint <Check-Point-Name> running-config
Rollback Config: Nexus# rollback running-config checkpoing <Check-Point-Name>

Nexus# show ip int brief | grep -i vlan
Nexus# show clock | ex NTP

routing-context vrf <VRF-NAME>
Show ip route
routing-context vrf default