cns-lab_11

7/27/2019 CNs-Lab_11

1/5

February 2013

Dr. Shareef CNs Lab 11 Page 1

Practical 11

Router configuration

In this session I will show how can you configure the router. For demonstration purpose I

used packet tracer software. Create a simple topology by dragging dives on workspace as

shown in the figure below:

Click inside the Router and select CLI and press Enter to get started. Setup mode starts

automatically if there is no startup configuration present. The answer inside the squarebrackets [ ], is the default answer. If this is the answer you want, just press enter. Pressing

CTRL+C at any time will end the setup process, shut down all interfaces, and take you to

user mode (Router>).

You cannot use setup mode to configure an entire router. It does only the basics. For

example, you can only turn on either RIPv1 or Interior Gateway Routing Protocol (IGRP),

but not Open Shortest Path First Protocol (OSPF) or Enhanced Interior Gateway Routing

Protocol (EIGRP). You cannot create access control lists (ACL) here or enable Network

Address Translation (NAT). You can assign an IP address to an interface, but not to a

subinterface. All in all, setup mode is very limited.

--- System Configuration Dialog --- Continue with configuration dialog?

[yes/no]:

Write no and press enter. To get router prompt

You are now connected to the Router and are in user mode prompt. The prompt is broken

down into two parts, the hostname and the mode. "Router" is the Router0's hostname and

">" means you are in user mode.

Press RETURN to get started

Router>

User mode is indicated with the '>' next to the router name. In this mode you can look at thesettings but cannot make changes.

In Privilege mode (indicated by the '#', you can do anything). To get into the privilege mode

the keyword is enabled.

Next type the command enable to get to the privileged mode prompt.

Router > enable

7/27/2019 CNs-Lab_11

2/5

February 2013


Router#

To get back to the user mode, simply type disable. From the user mode type logout orexit

to leave the router.

Router#disableRouter>

Router>exit

Router con0 is now available

Press RETURN to get started

Press enter to get back router prompt

Router>

You are now in User mode. Type ?to view all the available commands at this prompt.

Router>?

From privilege mode you can enter in configuration mode by typing configure terminal you

can exit configuration mode type exit or +z

Router>enable

Router#config terminal

Router(config)#exit

Router#

To view all commands available from this mode type ? and press enter. This will give you the

list of all available commands for the router in your current mode. You can also use the

question mark after you have started typing a command. For example if you want to use a

show command but you do not remember which one it uses 'show ?' Will output all

commands that you can use with the show command.

Router#show ?

access-expression List access expression

access-lists List access lists

backup Backup status

cdp CDP information

clock Display the system clock

cls DLC user information

compress Show compression statistics

configuration Contents of Non-Volatile memory--More--

Router boot and initial Configuration:

Do some basic configuration as you have done before with switch devices.Set a : name, password, enable secret , set IP address, ... etc.

7/27/2019 CNs-Lab_11

3/5

February 2013


Routing: Implementing Static Routing:

Understanding the Purpose of the Router:

A PC is connected to the network 192.168.1.0 with IP address 192.168.1.20 and connected to

the gateway (Router IP) 192.168.1.1, with a connection between the two routers in network

192.168.2.0, where the R1 IP address is 192.168.2.1 and R2 IP address is 192.168.2.2, and

finally R2 is connected to the other network 192.168.3.0 with IP address 192.168.3.1 and the

PC at the right is connected at IP address 192.168.3.20.

Now if I were logging console at R1, I would be able to ping the network 192.168.2.0, and

the network 192.168.1.0 because R1 is Directly Connected to those networks, now if R1

pings network 192.168.3.0, he will not get any replies cause R1 does not now that this

network Exist, although R1 is connected to R2 that is connected to network 192.168.3.0 but

R1 is not Smart enough to understand that R2 has the ability to get to that network, likewise

R2 knows how to reach Network 192.168.3.0 & 192.168.2.0, but doesnt know network

192.168.1.0 exist, the result is that PC at the Left cant communicate to the PC at the right,

because the routers are not yet routing.

How Static Routing Can Help:

Static routing is when you as an administrator get on the routers and start telling them where

to go (Manually).

Now we will access Router1 (R1) and see what interfaces is connected to, as from the (show

ip interface brief) command will show its connected Interfaces as in the above Picture,

FE0/0 is IP address 192.168.1.1 & the Serial Interface is 192.168.2.1

Then by using the same command (show ip interface brief) in R2, we will see that its

connected interface FE0/1 IP address is 192.168.3.1 & the Serial interface IP is 192.168.2.2.

7/27/2019 CNs-Lab_11

4/5

February 2013


After we have seen the two Routers with their Connection, we will move back to Router 1

and see what Network Address it knows. Lets do the Following:

R1#show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGPD - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set

C 192.168.1.0/24 is directly connected, FastEthernet0/0

C 192.168.2.0/24 is directly connected, Serial0/1/0

From the Above we see R1 had learned that network 192.168.1.0 & 192.168.2.0 are

connected to its interfaces, the Codes in the above tells you how the Router learned that

Network address by which Method, in our Picture it says it has Learned the Two Network

Address because they are directly connected to Router interfaces which is method Cwhich is

written at the Beginning of the line which refers to Connected means (those Networks are

Directly Connected to the Router).

BUT : Router1 (R1) cant connect to the network 192.168.3.0 & Router2 (R2) cant connect

to Network 192.168.1.0, so lets solve that using static routing as following:

R1(config)#ip route 192.168.3.0 255.255.255.0 ?

A.B.C.D Forwarding router's address

Ethernet IEEE 802.3

FastEthernet FastEthernet IEEE 802.3

GigabitEthernet GigabitEthernet IEEE 802.3z

Loopback Loopback interface

Null Null interface

Serial Serial

7/27/2019 CNs-Lab_11

5/5

February 2013


Vlan Catalyst Vlans

R1(config)#ip route 192.168.3.0 255.255.255.0 192.168.2.2

Ok as you see above we will write down the Command IP route where this is the Syntax for

Static Route, then we will choose the Destination networkaddress you want to go to, so Iwill write network 192.168.3.0 with its Mask. Then Question Mark to see what I have to get

to that network.

Then we have to specify the IP address of the next hop (Router) that let you reach the

network 192.168.3.0 with subnet mask 255.255.255.0 , which is 192.168.2.2.

It Means; I will use an IP address (192.168.2.2) that make me able to reach a network which

previously I dont know about it which is (192.168.3.0).

Lets See after the executing the previous Command if R1 has the information for reaching

network 192.168.3.0 or not:

R1#show ip route

Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP

i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area

* - candidate default, U - per-user static route, o - ODR

P - periodic downloaded static route

Gateway of last resort is not set

C 192.168.1.0/24 is directly connected, FastEthernet0/0

C 192.168.2.0/24 is directly connected, Serial0/1/0

S 192.168.3.0/24 [1/0] via 192.168.2.2

As you might see above it has the Method Swhich means Static route configured.

GOOD LUCK

cns-lab_11

Documents