4networking

Lesson 01 - Introduction to Cisco Certified Network Associate R&S

2019-06-03T11:38:00.003-07:00

The Cisco Certified Network Associate - Routing and Switching (CCNA - Routing and Switching ) certification title has become the leading entry level network certification available today. The Cisco Certified Network Associate - Routing and Switching (CCNA - Routing and Switching) certification was developed by Cisco to test a candidate's knowledge of networking at entry level. The Cisco Certified Network Associate - Routing and Switching (CCNA - Routing and Switching) certification analyzes the candidate's ability to install, configure, operate, and troubleshoot medium-size routed and switched networks.

The CCNA - Routing and Switching certification is recognized by IT employers when considering a fresher's profile for a vacancy or for a salary hike/promotion for experienced employees. The Cisco Certified Network Associate - Routing and Switching (CCNA - Routing and Switching) exam covers a broad range of networking concepts to prepare candidates for the technologies they are likely to work with in today’s network environments.

New version of CCNA Exam (Exam Number 200-120 CCNA Routing and Switching) is available from March 26, 2013. The last date for CCNA examination according to the old version (Exam Number 640-802 CCNA) is September 30, 2013. After September 30, 2013, only 200-120 CCNA Routing and Switching will be available. Please visit Cisco official CCNA Routing and Switching web page for more information.

CCNA exam syllabus includes TCP/IP, IP Addressing and Subnetting, Routing Information Protocol (RIP), Routing Information Protocol V2 (RIPv2), IGRP (Interior Gateway Routing Protocol), Enhanced Interior Gateway Routing Protocol (EIGRP), Open Shortest Path First (OSPF), Serial Line Interface Protocol, Frame Relay, VLANs, Ethernet, access control lists (ACLs) etc.

Thorough knowledge in Basic Networking and TCP/IP is required to continue CCNA Routing and Switching learning. If you are new to networking, we request you to click the following links to learn Basic Networking and TCP/IP.

The revised Cisco CCNA Routing and Switching topics as per 200-120 exam is listed below.

Operation of IP Data Networks

• Recognize the purpose and functions of various network devices such as Routers, Switches, Bridges and Hubs.
• Select the components required to meet a given network specification.
• Identify common applications and their impact on the network
• Describe the purpose and basic operation of the protocols in the OSI and TCP/IP models.
• Predict the data flow between two hosts across a network.
• Identify the appropriate media, cables, ports, and connectors to connect Cisco network devices to other network devices and hosts in a LAN

LAN Switching Technologies

• Determine the technology and media access control method for Ethernet networks
• Identify basic switching concepts and the operation of Cisco switches.
• Collision Domains
• Broadcast Domains
• Types of switching
• CAM Table
• Configure and verify initial switch configuration including remote access management.
• Cisco IOS commands to perform basic switch setup
• Verify network status and switch operation using basic utilities such as ping, telnet and ssh.
• Describe how VLANs create logically separate networks and the need for routing between them.
• Explain network segmentation and basic traffic management concepts
• Configure and verify VLANs
• Configure and verify trunking on Cisco switches
• DTP
• Auto negotiation

IP addressing (IPv4 / IPv6)

• Describe the operation and necessity of using private and public IP addresses for IPv4 addressing
• Identify the appropriate IPv6 addressing scheme to satisfy addressing requirements in a LAN/WAN environment.
• Identify the appropriate IPv4 addressing scheme using VLSM and summarization to satisfy addressing requirements in a LAN/WAN environment.
• Describe the technological requirements for running IPv6 in conjunction with IPv4 such as dual stack
• Describe IPv6 addresses
• Global unicast
• Multicast
• Link local
• Unique local
• eui 64
• autoconfiguration

IP Routing Technologies

• Describe basic routing concepts
• CEF
• Packet forwarding
• Router lookup process
• Configure and verify utilizing the CLI to set basic Router configuration
• Cisco IOS commands to perform basic router setup
• Configure and verify operation status of an ethernet interface
• Verify router configuration and network connectivity
• Cisco IOS commands to review basic router information and network connectivity
• Configure and verify routing configuration for a static or default route given specific routing requirements
• Differentiate methods of routing and routing protocols
• Static vs. Dynamic
• Link state vs. Distance Vector
• next hop
• ip routing table
• Passive interfaces
• Configure and verify OSPF (single area)
• Benefit of single area
• Configure OSPF v2
• Configure OSPF v3
• Router ID
• Passive interface
• Configure and verify interVLAN routing (Router on a stick)
• sub interfaces
• upstream routing
• encapsulation
• Configure SVI interfaces

IP Services

• Configure and verify DHCP (IOS Router)
• configuring router interfaces to use DHCP
• DHCP options
• excluded addresses
• lease time
• Describe the types, features, and applications of ACLs
• Standard
• Sequence numbers
• Editing
• Extended
• Named
• Numbered
• Log option
• Configure and verify ACLs in a network environment
• Named
• Numbered
• Log option
• Identify the basic operation of NAT
• Purpose
• Pool
• Static
• 1 to 1
• Overloading
• Source addressing
• One way NAT
• Configure and verify NAT for given network requirements
• Configure and verify NTP as a client

Network Device Security

• Configure and verify network device security features such as:
• Device password security
• Enable secret vs enable
• Transport
• Disable telnet
• SSH
• VTYs
• Physical security
• Service password
• Describe external authentication methods
• Configure and verify Switch Port Security features such as
• Sticky MAC
• MAC address limitation
• Static / dynamic
• Violation modes
• Err disable
• Shutdown
• Protect restrict
• Shutdown unused ports
• Err disable recovery
• Assign unused ports to an unused VLAN
• Setting native VLAN to other than VLAN 1
• Configure and verify ACLs to filter network traffic
• Configure and verify an ACLs to limit telnet and SSH access to the router

Troubleshooting

• Troubleshoot and correct common problems associated with IP addressing and host configurations.
• Troubleshoot and Resolve VLAN problems
• identify that VLANs are configured
• port membership correct
• IP address configured
• Troubleshoot and Resolve trunking problems on Cisco switches
• correct trunk states
• correct encapsulation configured
• correct vlans allowed
• Troubleshoot and Resolve ACL issues
• Statistics
• Permitted networks
• Direction
• Interface
• Troubleshoot and Resolve Layer 1 problems
• Framing
• CRC
• Runts
• Giants
• Dropped packets
• Late collision
• Input / Output errors

LAN Switching Technologies

• Identify enhanced switching technologies
• RSTP
• PVSTP
• Etherchannels
• Configure and verify PVSTP operation
• describe root bridge election
• spanning tree mode

IP Routing Technologies

• Describe the boot process of Cisco IOS routers
• POST
• Router bootup process
• Configure and verify operation status of a Serial interface
• Manage Cisco IOS Files
• Boot preferences
• Cisco IOS image(s)
• Licensing
• Show license
• Change license
• Differentiate methods of routing and routing protocols
• Administrative distance
• split horizon
• metric
• next hop
• Configure and verify OSPF (single area)
• neighbor adjacencies
• OSPF states
• Discuss Multi area
• Configure OSPF v2
• Configure OSPF v3
• Router ID
• LSA types
• Configure and verify EIGRP (single AS)
• Feasible Distance / Feasible Successors /Administrative distance
• Feasibility condition
• Metric composition
• Router ID
• Auto summary
• Path selection
• Load balancing
• Equal
• Unequal
• Passive interface
• IP Services
• Recognize High availability (FHRP)
• VRRP
• HSRP
• GLBP
• Configure and verify Syslog
• Utilize Syslog Output
• Describe SNMP v2 & v3

Troubleshooting

• Identify and correct common network problems
• Utilize netflow data
• Troubleshoot and Resolve Spanning Tree operation issues
• root switch
• priority
• mode is correct
• port states
• Troubleshoot and Resolve routing issues
• routing is enabled
• routing table is correct
• correct path selection
• Troubleshoot and Resolve OSPF problems
• Neighbor Adjacencies
• Hello and Dead timers
• OSPF area
• Interface MTU
• Network types
• Neighbor states
• OSPF topology database
• Troubleshoot and Resolve EIGRP problems
• neighbor adjancies
• AS number
• Load balancing
• Split horizon
• Troubleshoot and Resolve interVLAN routing problems
• Connectivity
• Encapsulation
• Subnet
• Native VLAN
• Port mode trunk status
• Troubleshoot and Resolve WAN implementation issues
• Serial interfaces
• PPP
• Frame relay
• Monitor NetFlow statistics
• Troubleshoot etherchannel problems

WAN Technologies

• Identify different WAN Technologies
• Metro Ethernet
• VSAT
• Cellular 3G / 4G
• MPLS
• T1 / E1
• ISDN
• DSL
• Frame relay
• Cable
• VPN
• Configure and verify a basic WAN serial connection
• Configure and verify a PPP connection between Cisco routers
• Configure and verify Frame Relay on Cisco routers
• Implement and troubleshoot PPPoE

Lesson 01 - why we have Limitations of IPv4

2019-06-03T11:31:00.001-07:00

The Internet Protocol Version 4 (IPv4) is defined by IETF RFC 791. RFC 791 was published in 1981. Initial design of IPv4 did not anticipate the growth of internet and this created many issues, which proved IPv4 need to be changed. The main limitations of IPv4 are listed below.

• Scarcity of IPv4 Addresses: The IPv4 addressing system uses 32-bit address space. This 32-bit address space is further classified to usable A, B, and C classes. 32-bit address space allows for 4,294,967,296 IPv4 addresses, but the previous and current IPv4 address allocation practices limit the number of available public IPv4 addresses. Many addresses which are allocated to many companies were not used and this created scarcity of IPv4 addresses.

Because scarcity of IPv4 addresses, many organizations implemented NAT (Network Address Translation) to map multiple private IPv4 addresses to a single public IPv4 address. By using NAT (Network Address Translation) we can map many internal private IPV4 addresses to a public IPv4 address, which helped in conserving IPv4 addresses. But NAT (Network Address Translation) also have many limitations. NAT (Network Address Translation) do not support network layer security standards and it do not support the mapping of all upper layer protocols. NATcan also create network problems when two organizations which use same private IPv4 address ranges communicate. More servers, workstations and devices which are connected to the internet also demand the need for more addresses and the current statistics prove that public IPv4 address space will be depleted soon. The scarcity of IPv4 address is a major limitation of IPv4 addressing system.

• Security Related Issues: As we discussed before, RFC 791 (IPv4) was published in 1981 and the current network security threats were not anticipated that time. Internet Protocol Security (IPSec) is a protocol suit which enables network security by protecting the data being sent from being viewed or modified. Internet Protocol Security (IPSec) provides security for IPv4 packets, but Internet Protocol Security (IPSec) is not built-in and optional. Many IPSec implementations are proprietary.

• Address configuration related issues: Networks and also internet is expanding and many new computers and devices are using IP. The configuration of IP addresses (static or dynamic) should be simple.

• Quality of service (QoS): Quality of Service (QoS) is available in IPv4 and it relies on the 8 bits of the IPv4 Type of Service (TOS) field and the identification of the payload. IPv4 Type of Service (TOS) field has limited functionality and payload identification (uses a TCP or UDP port) is not possible when the IPv4 datagram packet payload is encrypted.

Lesson 01 - Introduction to Information Security

2019-06-03T11:24:00.000-07:00

Security can be defined as state of freedom from a danger, risk or attack. Information security can be defined as the task of guarding information which is processed by a server, stored on a storage device, and transmitted over a network like Local Area Network or the public Internet. Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification or destruction

Introduction to AAA

AAA stands for Authentication, Authorization and Accounting. AAA are a set of primary concepts that aid in understanding computer and network security as well as access control. These concepts are used daily to protect property, data, and systems from intentional or even unintentional damage. AAA is used to support the Confidentiality, Integrity, and Availability (CIA) security concept.

Confidentiality: The term confidentiality means that the data which is confidential should remain confidential. In other words, confidentiality means secret should stay secret.

Integrity: The term integrity means that the data being worked with is the correct data, which is not tampered or altered.

Availability: The term availability means that the data you need should always be available to you.

Authentication provides a way of identifying a user, typically requiring a Userid/Password combo before granting a session. Authentication process controls access by requiring valid user credentials. After the Authentication process is completed successfully, a user must be given authorization (permission) for carrying out tasks within the server. Authorization is the process that determines whether the user has the authority to carry out a specific task. Authorization controls access to the resources after the user has been authenticated. The last one is Accounting. Accounting keeps track of the activities the user has performed in the server.

Lesson 01 - Introduction to TCP/IP

2019-06-03T11:17:00.003-07:00

What is TCP/IP?

TCP/IP is a set of protocols (Protocol Suit) that enable communication between computers. Protocols are rules or standards that govern communications. If two devices in a network need to communicate, they need to use a common protocol. This can be compared with how humans speak. A French person cannot communicate with a Vietnamese person since they speak different languages.

You can select from different network protocols to use in your network, but TCP/IP is the industry standard. Almost all Operating Systems now support TCP/IP. Internet is working on TCP/IP. TCP/IP is known as "the language of the Internet." If you want a computer to work on the Internet, you have to use TCP/IP.

Features of TCP/IP

The industry was using TCP/IP around 35 years. It is a tested and proved protocol suit.

1) Multi-Vendor Support. TCP/IP is implemented by many hardware and software vendors. It is an industry standard and not limited to any specific vendor.

2) Interoperability. Today we can work in a heterogeneous network because of TCP/IP. A user who is sitting on a Windows box can download files from a Linux machine, because both Operating Systems support TCP/IP. TCP/IP eliminates the cross-platform boundaries.

3) Logical Addressing. Every network adapter has a globally unique and permanent physical address, which is known as MAC address (or hardware address). The physical address is burnt into the card while manufacturing. Low-lying hardware-conscious protocols on a LAN deliver data packets using the adapter's physical address. The network adapter of each computer listens to every transmission on the local network to determine whether a message is addressed to its own physical address.

For a small LAN, this will work well. But when your computer is connected to a big network like internet, it may need to listen to millions of transmissions per second. This may cause your network connection to stop functioning.

To avoid this, network administrators often segment (divide) big networks into smaller networks using devices such as routers to reduce network traffic, so that the unwanted data traffic from one network may not create problem in another network. A network can be again subdivided into smaller subnets so that a message can travel efficiently from its source to the destination. TCP/IP has a robust subnetting capability achieved using logical addressing. A logical address is an address configured through the network software. The logical addressing system used in TCP/IP protocol suit is known as IP address.

4) Routability. A router is a network infrastructure device which can read logical addressing information and direct data across the network to its destination.TCP/IP is a routable protocol, which means the TCP/IP data packets can be moved from one network segment to another.

5) Name Resolution. IP addresses are designed for the computers and it is difficult for humans to remember many IP addresses. TCP/IP allows us to use human-friendly names, which are very easy to remember (Ex. www.omnisecu.com). Name Resolutions servers (DNS Servers) are used to resolve a human readable name (also known as Fully Qualified Domain Names (FQDN)) to an IP address and vice versa.

6) Error Control and Flow Control.The TCP/IP protocol has features that ensure the reliable delivery of data from source computer to the destination computer. TCP (Transmisssion Control Protocol) defines many of these error-checking, flow-control, and acknowledgement functions.

7) Multiplexing/De-multiplexing. Multiplexing means accepting data from different applications and directing that data to different applications listening on different receiving computers. On the receiving side the data need to be directed to the correct application, for that data was meant for. This is called De-multiplexing. We can run many network applications on the same computer. By using logical channels called ports, TCP/IP provides means for delivering packets to the correct application. In TCP/IP, ports are identified by using TCP or UDP port numbers.

TCP/IP History

The predecessor of today’s Internet was ARPAnet, created by the Advanced Research Projects Agency (ARPA) and launched in 1969 during "Cold War". The extreme distrust that existed between USA and USSR (Soviet Union) was almost on the verge of a nuclear war during that time. "Cold War" was the term used to describe the relationship between USA and USSR during period 1945 to 1990. ARPAnet was created in response to the potential threat of nuclear attack from the Soviet Union. One of ARPA’s primary goals was to design a fault-tolerant network that would enable U.S. military leaders to stay in contact in case of nuclear war.

The protocol used on the ARPAnet was called Network Control Protocol (NCP). As the ARPAnet grew, however, a new protocol was needed because NCP was not able to fulfil all the needs of a larger network.

In 1974 Vint Cerf and Bob Kahn, published a paper “A Protocol for Packet Network Interconnection.” This paper describes the Transmission Control Protocol (TCP), which eventually replaced NCP.

By 1978, testing and further development of this language led to a new suite of protocols called Transmission Control Protocol/Internet Protocol (TCP/IP). In 1982, it was decided that TCP/IP would replace NCP as the standard language of the ARPAnet. RFC 801 describes how and why the transition from NCP to TCP was to take place. On January 1, 1983, ARPAnet switched over to TCP/IP, and the network continued to grow very fast.

ARPAnet ceased to exist in 1990. The Internet has since grown from ARPAnet’s roots, and TCP/IP has evolved to meet the changing requirements of the Internet.

Requests For Comments (RFC)

Request For Comments (RFC) is a paper describing a protocol or technology. RFC's are used as a platform to encourage and facilitate correspondence among the engineers who are involved in developing a new technology or a protocol. RFCs help in providing feedback and collaboration among engineers. An RFC is a paper that has been written by an engineer, a team of engineers, or just someone who has an innovative idea, to define a new technology or enhance an existing technology. After an RFC is written and posted, it can be evaluated, and used by other engineers and developers. If another engineer or developer can improve on the theory or standard, the RFC provides an open forum to do so.

An RFC can be submitted for review to the IETF (Internet Engineering Task Force). Engineers from the IETF review the papers that are submitted and assign a number to each. From that point on, the RFC number becomes the effective "name" of the paper. There are currently more than 5,000 RFCs. RFC's can be searched in RFC search Engine, http://www.rfc-editor.org/rfcsearch.html, by using the RFC number or by the technology name.

Lesson 01 - Introduction to Computer Networking .

2019-06-03T11:03:00.000-07:00

Technologies are evolving so fast. Networking world has changed so much in last 25 years. These days, networks with speed of 10 Gbps (Giga bits per second) are becoming common. The speed of 10 Gbps was not even imaginable 25 years back.

These days, even the smallest organization has a connection to the Internet. Almost all companies have websites and have their presence on the World Wide Web. Companies now operate on networks and do get customers via internet. The beautiful world of computer networking is ever evolving.

Network engineers have most exciting and thrilling job. They are always updated in technology and they get the first chance to operate and work in latest technologies.

The basic nature of duty of a network engineer is to Design, Install, Administer and to Trouble-shoot computer networks. Therefore, a network engineer should have thorough knowledge about network infrastructure devices. A network engineer should have enough knowledge in how to Design, Install, Administer and to Trouble-shoot these devices.

A Network Engineer has a a wide range of responsibilities. Responsibilities of a Network Engineer may include :

• Managing company's computers

• Providing technical support to users

• Designing company's network

• Designing, Building and Maintaining and connections between offices (physical sites)

• Provisioning Internet and providing user access to internet

• Configuring user privileges access to internet

• Configuring user privileges in network

• Installing, configuring, managing and hardening Operating Systems

• Configuring Network Infrastructure Devices like Switches, Routers and Firewalls

• Hardening Network Infrastructure Devices like Switches, Routers and Firewalls

• Providing network security