Lesson No. 15 Configure the routers with class full network with RIP version 1.

Classful Network

let's first know little bit about classful network, what it is, how to implement it. A classful network is a network addressing architecture used in the Internet from 1981 until the introduction of Classless Inter-Domain Routing in 1993. The method divides the address space for Internet Protocol Version 4 (IPv4) into five address classes. Each class, coded in the first four bits of the address, defines either a different network size, i.e. number of hosts for unicast addresses (classes A, B, C), or a multicast network (class D). The fifth class (E) address range is reserved for future or experimental purposes.

Classful addressing, formally adopted as part of the Internet Protocol (IP) in RFC 791, was the Internet's first major addressing scheme. The IP address was 32 bits in size, just as today, but was managed considerably differently.

There were three address classes to chose from: A, B, or C, corresponding to 8-bit, 16-bit, or 24-bit prefixes. No other prefix lengths were allowed, and there was no concept of nesting a group of 24-bit prefixes, for example, within a 16-bit prefix.

Class	Leading bits	Size of network number bit field	Size of rest bit field	Number of networks	Addresses per network	Start address	End address
Class A	0	8	24	128 (27)	16,777,216 (224)	0.0.0.0	127.255.255.255
Class B	10	16	16	16,384 (214)	65,536 (216)	128.0.0.0	191.255.255.255
Class C	110	24	8	2,097,152 (221)	256 (28)	192.0.0.0	223.255.255.255
Class D (multicast)	1110	not defined	not defined	not defined	not defined	224.0.0.0	239.255.255.255
Class E (reserved)	1111	not defined	not defined	not defined	not defined	240.0.0.0	255.255.255.255

Configure the routers with class full network with RIP1

Description: The Routing Information Protocol (RIP) is a distance-vector protocol that uses hop count as it’s metric. RIP is widely used for routing traffic in the global Internet and is an interior gateway protocol, which means that it performs routing within a single autonomous system. Using RIP, a gateway host (with a router) sends its entire routing table to its closest neighbour host every 30 seconds. The neighbour host in turn will pass the information on to its next neighbour and so on until all hosts within the network have the same knowledge of routing paths, a state known as network convergence. RIP uses a hop count as a way to determine network distance.

Solution: The given topology is:

Steps:

Configuring steps for router0:

Router>enable

Router#config t

Router(config)#interface fa0/0

Router(config-if)#ip address 10.0.0.1 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#interface se2/0

Router(config-if)#ip address 20.0.0.1 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#router rip

Router(config-router)#network 10.0.0.0

Router(config-router)#network 20.0.0.0

Router(config-router)#exit

Configuring steps for router1:

Router>enable

Router#config t

Router(config)#interface fa0/0

Router(config-if)#ip address 30.0.0.1 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#interface se2/0

Router(config-if)#ip address 20.0.0.2 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#router rip

Router(config-router)#network 20.0.0.0

Router(config-router)#network 30.0.0.0

Router(config-router)#exit

Configuring steps for router2:

Router>enable

Router#config t

Router(config)#interface fa0/0

Router(config-if)#ip address 50.0.0.1 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#interface se2/0

Router(config-if)#ip address 40.0.0.2 255.0.0.0

Router(config-if)#no shutdown

Router(config-if)#exit

Router(config)#router rip

Router(config-router)#network 40.0.0.0

Router(config-router)#network 50.0.0.0

Router(config-router)#exit

Output:

Ping command from PC5 to PC1

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Lesson No. 14 Basic router configuration

Basic router configuration

following commands are used in basic router configuration. Have a look at them and grasp them quickly.

Following are the basic commands:

1.        Naming the router

Use: Specifies the name for the router.

Steps:

Router>enable

Router# configure terminal

Router# hostname bca

bca>

Output:

2.        Setting passwords

·         Secret password

Use: Specifies an encrypted password to prevent unauthorized access to the router.

Steps:

bca(config)# enable secret chitkara

Output:

·         Setting console terminal password

Use: Enters line configuration mode, and specifies the console type of line then give unique password for line and enable password checking at terminal session login.

Steps:

bca(config)# line console 0

bca(config-line)# password abc

bca(config-line)# login

bca(config-line)# exit

bca(config)#

Output:

·         Setting virtual terminal password

Use: Specifies a virtual terminal for remote console access.

Steps:

bca(config)# line vty 0 4

bca(config-line)# password def

bca(config-line)# login

bca(config-line)# exit

bca(config)#

Output:

3.        Configuring interfaces

·         Fast Ethernet interface

Use: Enters interface mode and then give ip address, subnet mask.

Steps:

bca(config)# interface fa0/0

bca(config-if)# ip address 192.168.10.1 255.255.0.0

bca(config-if)# no shutdown

bca(config-if)# exit

Output:

·         Serial interface

Use: Enters serial interface mode and then give ip address, subnet mask and clock rate. Clock rate will be given only if the serial port is DCE.

Steps:

bca(config)# interface se0/0

bca(config-if)#ip address 192.168.30.1 255.255.0.0

bca(config-if)#no shutdown

bca(config-if)# clockrate 6400

bca(config-if)#exit

Output:

4.        Message of the banner

Use: Message will be shown when we enter the command line interface of the router.

Steps:

bca(config)# banner motd %message....%

bca(config)#

Output:

Output:

Ping command from PC1 to router

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Lesson No. 13 Telnet and SSH on packet tracer

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Telnet and SSH on packet tracer

A terminal emulation program for TCP/IP networks such as the Internet. The Telnet program runs on your computer and connects your PC to a server on the network. You can then enter commands through the Telnet program and they will be executed as if you were entering them directly on the server console. This enables you to control the server and communicate with other servers on the network. To start a Telnet session, you must log in to a server by entering a valid username and password. Telnet is a common way to remotely control Web servers. To telnet means to establish a connection with the Telnet protocol, either with command line client or with a programmatic interface. 

SSH 

Secure Shell (SSH) is a cryptographic network protocol for secure data communication, remote shell services or command execution and other secure network services between two networked computers that connects, via a secure channel over an insecure network, a server and a client (running SSH server and SSH client programs, respectively). It was designed as a replacement for Telnet and other insecure remote shell protocols such as the Berkeley rsh and rexec protocols, which send information, notably passwords, in plaintext, rendering them susceptible to interception and disclosure using packet analysis. The encryption used by SSH is intended to provide confidentiality and integrity of data over an unsecured network, such as the Internet.

a network protocol that ensures a high-level encryption, allowing for the data transmitted over insecure networks, such as the Internet, to be kept intact and integrate. SSH and SSH Telnet, in particular, work for establishing a secure communication between two network-connected computers as an alternative to remote shells, such as TELNET, that send sensitive information in an insecure environment. 

In contrast to other remote access protocols, such as FTP, SSH Telnet ensures higher level of connection security between distant machines but at the same time represents a potential threat to the server stability. Thus, SSH access is considered a special privilege by hosting providers and is often assigned to users only per request. 

Let us apply Telnet and SSH on packet tracer.

 

Take the topology as in the above diagram. Set IPs on the PCs. As, by default, all PCs are in vlan 1. We will create a virtual interface on switch with vlan 1 as follows.

 

Now, we can ping to switch by our hosts because hosts are in vlan 1 and switch also has a vlan 1 interface.

 

Now, try to telnet the switch from our PC, it refuses because we have not applied authentication on the switch yet.

 

So, lets apply line authentication on the switch. The system supports 20 virtual tty (vty) lines for Telnet, Secure Shell Server (SSH) and FTP services. Each Telnet, SSH, or FTP session requires one vty line. You can add security to your system by configuring the software to validate login requests. 

 

Now, we can easily telnet. But it does not let us go in the switch enabled mode because we have not set the password on the switch yet.

 

Lets apply password on the switch enabled mode.

 

Now, we can go inside Switch configuration mode from our pc.

 

So, now let us apply SSH on the switch.

 

Commands continued.

 

Now, we try to telnet it but it is refused because ssh has over ruled telnet. So, we will use SSH protocol on it. By default username is admin.

 

And we can apply any sort of configuration on our switch from out pc.

 

Now, if we want to change the username from admin to something else, we will do it as follows.

and from our pc as follows.

The SSH commands are as follows.

Switch(config)#ip domain name ?
 WORD  Default domain nameSwitch(config)#ip domain name abc.comSwitch(config)#crypto key generate rsa
% Please define a hostname other than Switch.

Switch(config)#hostname s1

s1(config)#ip domain name cs-studys1
s1(config)#crypto key generate rsa
Choose the size of the key modulus in the range of 360 to 2048 for your General Purpose Keys. Choosing a key modulus greater than 512 may take   a few minutes.
s1(config)#line vty 0 15 s1(config-line)#transport input ssh

The name for the keys will be: s1.cs-study

How many bits in the modulus [512]: 1024

% Generating 1024 bit RSA keys, keys will be non-exportable...[OK]

s1(config)#ip ssh version 2

s1(config-line)#

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Lesson No 12 Accessing remote devices using telnet.

Accessing remote devices using telnet.

Telnet is a user command and an underlying TCP/IP protocol for accessing remote computers. Through Telnet, an administrator or another user can access someone else's computer remotely. On the Web, HTTP and FTP protocols allow you to request specific files from remote computers, but not to actually be logged on as a user of that computer. With Telnet, you log on as a regular user with whatever privileges you may have been granted to the specific application and data on that computer.

Description: Telnet is to gain access to a terminal/command prompt so a person can make changes to the system. While Windows, UNIX, and Linux, have GUI's available to change system setting, many (if not all) setting can still be modified through the command prompt. Some things can only be changed via command prompt. Telnet lets system administrators remotely access and work on a system. 

Solution: The given topology is:

    

Steps:

Following are the PC’s attached to switch0:

Configuring steps for PC0:

Ip address: 192.16.10.33

Subnet mask: 255.255.255.248

Default gateway: 192.16.10.34

Configuring steps for PC1:

Ip address: 192.16.10.38

Subnet mask: 255.255.255.248

Default gateway: 192.16.10.34

Configuring steps for PC2:

Ip address: 192.16.10.1

Subnet mask: 255.255.255.224

Default gateway: 192.16.10.2

Configuring steps for PC3:

Ip address: 192.16.10.30

Subnet mask: 255.255.255.248

Default gateway: 192.16.10.2

Configuring steps for router0 from PC0:

Router>enable

Router#config terminal

Router(config)#enable password abc

Router(config)# interface fa0/0

Router(config-if)# ip address 192.16.10.34 255.255.255.248

Router(config-if)# no shutdown

Router(config-if)# exit

Router(config)#interface se2/0

Router(config-if)#ip address 192.16.10.41 255.255.255.252

Router(config-if)#no shutdown

Router(config-if)#clock rate 64000

Router(config-if)#exit

Router(Config)#router rip

Router(config-router)#version 2

Router(config-router)#network 192.16.10.0

Router(config-router)#exit

Configuring steps for router1:

Router>enable

Router#config terminal

Router(config)# line vty 0 4

Router(config)#password cisco

Router(config)#login

Router(config)#exit

Router# configure terminal

Router(config)#enable password abc

Router(config)#line console 0

Router(config)#password line

Router(config)#login

Router(config)#exit

Router#configure terminal

Router(config)# interface fa0/0

Router(config-if)# ip address 192.16.10.2 255.255.255.227

Router(config-if)# no shutdown

Router(config-if)# exit

Router(config)#interface se2/0

Router(config-if)#ip address 192.16.10.42 255.255.255.252

Router(config-if)#no shutdown

Router(config-if)#exit

Router(Config)#router rip

Router(config-router)#version 2

Router(config-router)#network 192.16.10.32

Router(config-router)#exit

Router(config)#

Output:

Telnet command from PC1 to router1

     

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