IT & I

Freedom & Ubuntu

2011-06-09T11:11:00.000-07:00

Writers: Matthew Helmke,
Andrew Hudson, Paul Hudson
Language: English
Paperback: 769 pages
Data: March 15, 2011
Format: PDF
FREE DOWNLOAD!

PuTTY Config!

2011-06-08T16:52:00.000-07:00

PuTTY is a free and open source terminal emulator application which can act as a client for the SSH, Telnet, logging, and raw TCP computing protocols and as a serial console client. The name "PuTTY" has no definitive meaning, though 'tty' is the name for a terminal in the Unix tradition, usually held to be short for teletype.

PuTTY was originally written for Microsoft Windows, but it has been ported to various other operating systems. Official ports are available for some Unix-like platforms, with work-in-progress ports to Classic Mac OS and Mac OS X, and unofficial ports have been contributed to platforms such as Symbian and Windows Mobile.

PuTTY Vs. Telnet? PuTTY win! download

router name# show interface status

address |ـــــ add

ARP (Address Resolution Protocol)

2011-05-28T18:06:00.000-07:00

It help ip network devices find other device on the same segment or Vlan |ـــــ ARP uses a local broad cast to discover neighboring device |ـــــ ARP resolves ip addresses to mac addresses so that machines on the same data link layer media can communicate with each other.

Protocol       Protocol ID
Internet Control Message Protocol (ICMP)            1
Transmission Control Protocol (TCP)            6
Interior Gateway Routing Protocol (IGRP)                   9
User Datagram Protocol (UDP)                  17
Internet Protocol version 6 (IPv6)               41
Internet-work Packet Exchange (IPX)         111

Internet Control Message Protocol (ICMP)

2011-05-28T17:00:00.000-07:00

It is used to send error & control information between ip network devices.
There are many diffident messages that can be shared, including the following:

1. Echo request: Determines whether on ip node ( a host or a router is available on network.)
2. Echo Reply: Replies to ICMP echo request.
3. Destination Unreachable: Informs the host that a datagram can't be delivered.
4. Source Quench: Informs the host to lower the rate at which it sends datagram because of congestion.

5. Redirect: Informs the host of a preferred rate.

6. Time Exceeded: Indicate that the TTL of IP datagram has expired.

What is Datagram?

2011-05-21T01:11:00.000-07:00

A datagram is a basic transfer unit associated with a packet-switched network in which the delivery arrival time and order are not guaranteed. A datagram consists of header and data areas, where the header contains information sufficient for routing from the originating equipment to the destination without relying on prior exchanges between the equipment and the network. The source and destination addresses as well as a type field are found in the header of a datagram.
The term datagram is often considered synonymous to "packet", but there are some nuances. First, the term packet applies to any message formatted as a packet, while the term datagram is generally reserved for packets of an "unreliable" service. An "unreliable" service does not notify the user if delivery fails. For example, IP itself provides an unreliable service and UDP over IP also provides an unreliable one. That is why UDP packets are generally called datagrams. Second, if a datagram fragments, then its fragments may be referred as packets, but not as datagrams. However, TCP refers to its fragments as TCP segments, not packets, presumably to assert that its fragments are reliable.

Any thing About cisco Security Device Manager (SDM)

2011-05-15T20:08:00.000-07:00

Part 3

Installing Cisco Security Device Manager (SDM)

Part 1

Part 2

Security Device Manager (SDM) - Cisco CCNA Security Training

Do you want to have FREEDOM ?

2011-05-14T22:33:00.000-07:00

Publisher: Hall PTR
Language: English
ISBN: 0132435942
Paperback: 448 pages
Data: August 11, 2006
Format: PDF

Publisher: Apress
Language: English
ISBN: 1590596277
Paperback: 608 pages
Data: March 15, 2006
Format: PDF

Using the Pipe

2011-05-13T12:25:00.000-07:00

It is the output modifier. This pipe ( | ) allow us to wade through all the configurations or other long out puts & get straight to our goods fast.

Arman#sh run | ?
Append Append redirected out put to URL ( URLs supporting append operation only )
Begin Begin with the line that matches.

Exclude Exclude line that match.
Include Include line that match.
Redirect Redirect out put to URL.
Section Filter a section of out put.
Tee Copy out put to URL.

Arman#sh run | begin interface

interface fast Ether net 0/0

description sales VLAN

ip address 10.10.10.1 255.255.255.248

duplex auto

Speed auto

interface fast Ethernet 0/1

Setting up SSH

2011-05-07T09:09:00.000-07:00

Which creates a more secure session than the Telnet app that use an uncrypted data stream.
Here are the steps to setting up SSH:
1. Set your host name:
Router(config)#host name Rezakhani

2. Set the domain name (both the host name & domain name are required for the encryption keys to be generated) :
Rezakhani(config)# ip domain -name ArmanRezakhani.com

3. Generate the encryption keys for security the session:
Rezakhani(config)# crypto key generate rsa general -keys modulus ?
<360-2048> size of the key modulus [360-2048]
Rezakhani(config)# crypto key generate rsa general -keys modulus 1024

- The name for keys will be Rezakhani.ArmanRezakhani.com
- % The key modulus size is 1024 bits

- % Generating 1024 bit RSA keys, will be non-exportable ...[Ok]
- * June 24 9:25:30.035: %SSH-5-ENABLED: SSH 1.99
has been enabled.

4. Set the max idle timer for a SSH Session:
Rezakhani(Config)# ip SSH time -out ?
<1-120> SSH time -out interval (secs)
Rezakhani (config)# ip ssh time -out 60

5. Set the max failed attempts for an SSH connection:
Rezakhani(config)# ip ssh authentication -retries ?
<0-5> number of authentication retries
Rezakhani (config)# ip ssh authentication -retries 2

6. Connect to the vty line of the router:
Rezakhani (config)# line vty0 1180

7. last, configure SSH & the Telnet as access protocols:
Rezakhani (config-line)# than sport input ssh telnet.

If you do not use the key word telnet at the end of the command string, then only SSH will work on the router.
I am not suggesting you use either way, but just understand that SSH is more secure than Telnet

*** You can download the SSH software here, called PuTTY ***

Do command

2011-05-07T04:44:00.000-07:00

** Beginning with IOS version 12.3

Cisco has finally added a command to the IOS that always you to view the configuration & statics from within configuration mode.

** In fact with a pre -12.3 router,

you'd get the following error if you tried to view the configuration from global - Config

you see:

Router (config)# sh run

^
% invalid input detected at ' ^ ' marker

Compare that to the output i got from entering that same command on my router that's running the 12.4 IOS

Enter configuration commands, one per line. End with CNTL/Z

Hot (config)# do show ru

Building configuration...

Current configuration : 3276 bytes

[out put cut]

Hot (config)# do sh int f0/0

FastEthernet 0/0 is UP, line protocol is down

Hardware is MV96340 Ethernet, address is 001a.2f55.c9e8

Description: sales Vlan

[out put cut]

** going back to the example of encrypting our passwords the do command would definitely have gotten the party started sooner

so, my friends, this is a very, very good thing indeed

OSI v TCP/IP

2011-05-06T03:33:00.000-07:00

OSI:

you can see it, HERE

TCP/IP:

Rout able: it can pass through routers.
Connect dissimilar systems: Win, Mac, Unix, etc...
Method of access to the inventor.

App Layer: using an app, it gains access to the network.

Telnet, FTP, TFTP , NFS, SMTP, LPD, DNS, DHCP.

Transportation: provides communication sessions between the two computers. TCP, UDP

Internet Layer: routers the data from it's source to it's source to its destination. ARP, RARP, IP, ICMP, IGMP.

Network Layer: it sends & receive data on the wire. Ethernet, Token Ring, Frame, Relay, ATM

(Well-Know Port Numbers:

FTP: 20 & 21, SMTP: 25, DNS: 53, Telnet:23, HTTP: 80, HTTPS: 443)

** IMPORTANT FIELDS

TCP Segment:

Source port: sending App port number
Destination port: receiving App number
Sequence number: maintains reliability & sequencing
Acknowledgement number: used to acknowledge received segments formation .
Windows: the number of segments that are allowed to be sent before waiting for an acknowledgement from the destination.
Checksum: CRC of the header & data.
Data: user App information.

Subneting class c addresses Normal Way!

2011-05-04T15:33:00.000-07:00

Before i start this article i should say don't worry if you can't understanding it! you can see the fast way!

- In class C address, only 8 bits are available for defining the hosts.
- Remember that subnet bits start at the left & go to the right without skipping bits.
- This means that the only class C subnet mask can be following.

Binary Decimal CIDR
00000000 0 /24
10000000 128 /25
11000000 192 /26
11100000 224 /27

** We can't use /31 or /32 because we have to at least 2 host bits for assigning IP address to hosts

Robots & Transportation Network

2011-05-04T11:11:00.000-07:00

فیلم ساخت و عملکرد یک شبکه حمل و نقل اتوماتیک به وسیله لگو و ربات‌های مختلف

Construction methods and performance of a transportation network by automated various robots

نکاتی‌ در مورد امنیت شبکه (PERSIAN)

2011-05-02T21:09:00.000-07:00

امنیت شبکه یکی‌ از مورد بسیار بسیار مهم می‌باشد که جا دارد به آن پرداخته شود.

وقتی‌ که از امنیت شبکه صحبت می‌کنیم شامل مورد بسیار زیادی میشود که هر کدام از آنها به تنهای میتواند مورد بحث قرار گیرد،همیشه در امنیت شبکه موضوی که بسیار اهمیت دارد لایه‌های دفأعی یک شبکه می‌باشد، باید یاد آوری کرد که اولین لایه دفأعی در امنیت شبکه و حتا امنیت فیزیکی‌ وجود یک ساختار و خط مشی‌ (policy) می‌باشد که بدون آن ،لیست کنترل ، فایروال و هر لایه دیگری بدون معنی می‌باشد دقیقا مثل ساختمانی می‌باشد که پایه ندارد !

برای داشتن policy باید پنج مرحله را در نظر داشت:

۱-بازرسی (inspection)

۲-حفاظت (protection)

۳-ردیابی (detection )

۴-واکنش (reaction )

۵-بازتاب (reflection )

برای اینکه شبکه امنی‌ داشته باشیم باید همیشه این پنج مرحله را در نظر داشته باشیم.

اولین جای که باید در شبکه ایمن سازی شود،ایمن کردن تمامی سندیت‌های (authortication) موجود می‌باشد.

رایجترین روش استفاده از شناسه کاربری و کلمه رمز است که به این مورد را باید در نظر داشت:

-بر رسی‌ و کنترل کلمات عبور کلیه کاربران به ویژه مدیرن سیستم.

-کلمات عبور برای سویچ‌ها و رتر‌ها که بسیار مهم می‌باشد.

-کلمات عبور مربوط به SNMP

-کلمات عبور مربوط به پرینت سرور

-کلمات عبور مربوط به محافظ صفحه نمایش

در واقعه شما باید امنیت کاملی را برای account password security در نظر داشته باشید.

دومین مورد، نصب و به روز رسانی آنتی ویروس‌ها روی همه کامپیوتر ها،سرور‌ها و میل سرور‌ها و وب سرور‌ها می‌باشد و همینطور به روز رسانی آنتی ویروس‌ها روی کامپیوتر کاربر‌ها باید به صورت اتوماتیک انجام شود و در صورت مشاهده مورد مشکوک حتما اقدامات امنیتی لازم انجام شود.

سومین مورد شامل نصب و به روز رسانی سیستم عامل و حفره‌های امنیتی سیستم‌های موجود است. باید حفره‌های امنیتی کلیه سرور ها، سوئیچ‌ها و روتر‌ها ، شناسایی و رفع شود و سرویس‌های غیر ضروری حذف و غیر فعال گردد.

چهارمین مورد که بسیار مهم است، دسته بندی کاربران و دادن سطح دسترسی مناسب با کار هر کاربر به آنها می‌باشد که همه نتوانند به همه فآیلها و دایرکتوریها دسترسی‌ داشته باشند.

پنجمین مورد، کنترل و config کردن device‌های موجود که شامل روتر ، سوئیچ و فایروال میباشد، که همه آنها باید بر اساس policy موجود در شبکه و با توجه به توپولوژی شبکه config شود .

تکنولوژی‌های مثل PAT, NAT, Filtering و غیره در این مرحله وجود دارد و به همین خاطر این مرحله یکی‌ از مهمترین مراحل امنیت یک شبکه می‌باشد.

مرحله بعدی، که آن هم بسیار مهم است داشتن یک استراتژی برای پشتیبانی‌ (backup ) است و اینکه مطمئن باشیم که این سیستم به درستی‌ کار می‌کند.

سپس باید به امنیت فیزیکی یک شبکه بپردازیم که شامل UPS‌ها میشود و باید مطمئن باشیم که آنها درست کار میکنند و اینکه اتاق سرور از درجه حرارت و رطوبت مناسب برخوردار باشد و همین طور در برابر سرقت و آتش سوزی هم ایمن باشد.به طور کلی‌ هر چیزی که مربوط به فیزیک شبکه میشود در این قسمت وجود دارد.

سپس باید به برسی‌ و تنظیم و آزمایش سیستم‌های auditing و logging می‌پردازیم این سیستم‌ها میتواند هم بر پایه host و هم بر پایه network باشد، سیستم‌های ردگیری و ثبت حملات هم در این مرحله نصب و تنظیم میگردد،باید کاملا اطمینان حاصل کنیم که تمام اطلاعات لازم ثبت شده و به خوبی‌ محافظت میگردد.

در ضمن درست بودن ساعت و تاریخ سیستم‌ها خیلی‌ مهم است چرا که در غیر این صورت امکان ردّ گیری و پیگیری قانونی در صورت لزوم وجود نخواهد داشت.

نکته دیگری که باید توجه داشته باشیم ایمن کردن Remote Access با پروتکل و تکنولوژی‌های امن.

باید در این قسمت با توجه به شرایط و امکانات ، ایمن‌ترین پروتکل و تکنولوژی‌ها را باید به خدمت گرفت.

نکته دیگر اینکه نصب فایروال‌های شخصی‌ در ساعت host‌ها و لایه‌های امنیتی مضاعفی به شبکه شما میدهد که بسیار مهم است، پس نصب فایروال‌ها را فراموش نکنید.

نکته آخر: شرایط بازیابی در حالت‌های ضروری را حتما بر رسی‌ کنید و به روز رسانی کنید این‌ها شامل خرابی‌ قطعات کامپیوتری، خرابکاری کاربران و خرابی‌ نشی‌ از مسأیل طبیعی ، نفوذ هکر‌ها به سیستم می‌باشد. استاندارد‌های Warm site و Hot site را حتما رعایت کنید و به خاطر داشته باشید که اطلاعات باید همیشه در دسترس و محفوظ باشد و اینکه حتما در سایت‌های خبری و بولتن‌های امنیتی عضو شوید و اطلاعات خود را همیشه به روز کنید!

VLAN Video Learning (ENGLISH)

2011-05-01T15:06:00.000-07:00

How to create Subnets

2011-05-01T10:42:00.000-07:00

To create subnetworks you take bits from the host portion of the ip address & reserve them to define the subnet address.

This means fewer bits for hosts, so the more subnets the fewer bits available for defining hosts.

1. Determine the number of required network IDs:

One for each subnet.
One for each wide area network connection.

2. Determine the number of required host IDs per subnet:

One for each TCP/IP.
One for each router interface.

3. Based on the above requirements, create the following:

One subnet mask for your entire network.
A unique subnet ID for each physical segment.
A range of host IDs for each subnet.

IP Subnet-Zero

2011-05-01T10:15:00.000-07:00

This command allows you to use first & last subnet in your network design.
FOR EXAM:
The class C mask of 192 provides subnets 64 & 128.
BUT with the ip subnet-zero command, you now get to use subnets 0 , 64, 128 & 192.
* that is two more subnets for every subnet mask use.

Subneting a class C address * THE FAST WAY! *

2011-04-29T16:11:00.000-07:00

You need to do is answer five simple questions:

How many subnets does the chosen subnet mask produce?
How many valid hosts per subnet are available?
What are the valid subnets?
what's the broad cast address of each subnet?
what are the valid hosts in each subnet?

well ...

1: 2^x = Number of subnets
X is the number of masked bits, or the 1s.

FOR EXAM: in 11000000 the number of 1s gives us 2^2 subnets.
- in this example, there are 4 subnets.

2: 2^y - 2 = Number of hosts per subnet.
Y is the number of unmasked bits, or the 0s.

FOR EXAM: in 11000000 the number of 0s gives us 2^6 - 2 hosts.
- in this example, there are 62 hosts per subnet address & the broad cast address, which are NOT valid hosts.

3: 256-subnet mask = block size, or increment number.
FOR EXAM: would be 256 - 192 = 64
the block size of 192 mask is always 64.
bin: 11000000     dec: 128+64+0+0+0+0+0+0=192
star counting at zero in block of 64 untill you rich the subnetmask.
value & these are your sub-nets. 0, 64, 128, 192.   Easy, huh?   0, (+64) 64, (+64) 128, (+64) 192

4: since we ciunted our subnets in the last section as 0, 64, 128 & 192. the broad cast address is always the number right befor the next subnet!

FOR EXAM: the subnet has a broadcast address of 127 because the next subnet is 128.
and so on!! remember, the broad cast address of the last subnet is always 255.

5: valid hosts are the number between the subnet, all 0s & all 1s.
FOREXAM: if 64 is the subnet number & 127 is the boardcast address then 65 - 126 is the valid host range. it's always the numbers between the subnet address & the broadcast address.

Cisco Switch 2600 Presentation!

2011-04-28T22:12:00.000-07:00

LAN & WAN Interface Descriptions

2011-04-24T19:17:00.000-07:00

LAN Interface Descriptions:

Atlanta (Router`s name) (config)# int e0
Atlanta (config-if)# description sales lan
Atlanta (config)# int e1
Atlanta (config-if)# description marketing lan

WAN Interface Descriptions

Titanic (Router`s name) (config-if) int e1
Titanic (config-if)# desc wan to maimai circuit: anythings!

Start up -config (NVRM) & Running -config (RAM) Moving: RAMNVRAMTFTP Server

copy commands: COPY (SENDER)(RECEIVER)

Show interface ? that will reveal all the available interface to cinfigure
Show ip interface (layer3)

Status of the interafce
The ip address & mask
Information on whether an access list is sent on interface.
Basic ip interface

3.Show ip interface brief quick over view --> logical address & Status

4.Show controllers

This command displays information about the physical interface it self.
Type of serial cable plugged into a serial port.
Usually, this will only be a DTE cable That plugs into a type of Data Service Unit (DSU)

Router Interface Configuration

2011-04-24T17:55:00.000-07:00

* IP addresses *Media Type * Bandwidth * Other administrative commands

Cisco 2522

Cisco 2522 has 10 serial:

Router (config)# int Serial?

<0-9> serial interface number

The 2522 router has one Ethernet 10baset port; Router (config)# int ethernet ?

<0-0> Ethernet interface number

Router (config)# int ethernet 0

Router (config-if)#

+ The 2600, 3600, 4000 & 7000 Series router USE a " Physical slot in the router, with a port number on the module plugged info that slot"

+ MUST type the full command; as same as: int fast ethernet 0/0 or int fa0/0. "slot/port"

Router (config)#int fa0/0

Router (config-if)# media -type ?

100base x use Rj-45 for -tx, SC F0 for -fx

MII use MII connector

* Default: interface command is OFF, shutdown. To turn on interface ON: no shutdown. [important because if shutdown will NOT send packets]

HOW?!

Router # config

(Enter configuration commands, one per line. End with Ctrl+Z)

Router (config)# int ethernet 0

Router (config-if)# no shutdown

Router (config-if) # ^z

00:57:08: %link -3- up down: interface ethernet 0, changed state to up 00:57:09: %link port -5- up down: line protocol on interface ethernet 0, changed state to up

Router#sh int ethernet 0

ethernet 0 is up line protocol is up

configuring ip address

Router (config)#int e0

Router (config-if)# ip address 172.16.10.2 255.255.255.0

Router (config-if)#no shut

+ Ip address verification with the: show running -config command sh run for short

+ Cisco router support two proprietary serial connections:

60-pin serial connector.
Smart serial: about 1/10 the size of the 60-pin.

DCE (Data Communication Equipment); Service provider "CSU". DCE requires a DCE cable.

DTE (Data Terminal Equipment); End user device "Router". DTE requires a DTE cable.

the Router

2011-04-23T18:03:00.000-07:00

Connecting to the Router

We have three ways:

Auxiliary Port / Phone line

Console Port / Rj-45 / Console Cable or Console cable-rollover

Telnet / (USER MODE) ip net - 10Baset t

Cisco Router Components

Bootstrap: boot the router & then load the IOS. [Microcode of the Rom]
POST (Power On Self Test): check the basic functionality of the router hard ware. [Microcode of the Rom]
Rom monitor: testing & troubleshooting. [Microcode of the Rom]
Mini-IOS (Rx-boot / boot-loader): small IOS in Rom. load a Cisco IOS into flash memory.
RAM: hold packet buffers, ARP cache, routing table.
ROM: star & main tent the router.
Flash memory: hold the Cisco IOS, NOT erased when the routers is reloaded, it is EEPROM.
NVRAM: hold the router & switch configuration.

Cisco Router

Summary:

Basic IOS: ROM
Boot strap: ROM
Diagnestics: ROM
Current IOS: Flash
Start up configuration: NVRAM
Running configuration: RAM

Types of IP addresses

2011-04-23T17:04:00.000-07:00

Types of addresses are: 1-Unicast 2-Multicast 3-Broadcast

First Network ID Last Network ID

Class A 1.0.0.0 126.0.0.0

Class B 128.0.0.0 191.255.0.0 127.0.0.1 is Loop Back

Class C 192.0.0.0 223.255.255.0

Mac Address 48-bit (6-byte) = OUI 24-bit + Vender Assigned 24-bit

NAT:

Class A: 10.0.0.0 through 10.255.255.25

Class B: 172.16.0.0 thought 172.31.255.255

Class C: 192.168.0.0 thought 192.168.255.255

OSI Layers

2011-04-22T11:19:00.000-07:00

1. Physical

2. Data link
3. Network

4. Transmission

5. Session

6. Presentation

7. Application

Physical:

1.1 Network connection types (Rj-45...)

1.2 Physical network topology (Bus...)

1.3 Bit encoding

1.4 Channel use

2. Data link:

2.1 Organizing the bits

2.2 The IEEE 802 standard

2.2.1 Media Access Control (MAC)

Logical Topology
Media access Method
Addressing

2.2.2 Logical Link Control (LLC)

Transmission Timing

Error Control

Flow Control

3. Network:

3.1 Network Addressing
3.2 Packet Switching (PDVs)
3.3 Routing

4. Transmission:

4.1 Segment Sequencing
4.2 Error Control
4.3 End of End flow control

5. Session:

5.1 Connection Manager
Simplex (T.V)

Half - Duplex (Walki-Taki)

Full - Duplex

5.2 Session Manager

6. Presentation:

6.1 Data Formating Translation
6.2 Data Encryption

7. Application (Firewall)

First post!

2011-04-21T21:52:00.000-07:00

This blog will continue till i take CCIE & prove my language!