Cisco How to : Cisco Routing Configurations

How to Configure Static routing

First of all lets configure static routing in the form of default routing on the cisco routers. This lab is done in gns3 and with 2691 router series on Microsoft Windows Xp.

What we are going to do in this lab is we will connect our routers running inside gns3 to the internet through Microsoft loopback adapter.

Detailed description of the diagram:

As you can see in the figure , There is an internet cloud which i have used to represent internet connection. I have attached microsoft loopback adapter to this cloud and

Configured Internet connection sharing between the physical interface (ie interface connected to the internet physically) and loopback adapter. so that my loopback adapter

is connected to the internet. (note: do not configure your physical interface with ip range 192.168.0.0/24 as this is the range given to loopback adapter while configuring internet

connection sharing). The loopback adapter is connected to our router R1.. We will be configuring static routing in this router as a result the router can connect to internet. We will

test this by sending ping packets to various sites on the internet.

Configuration

1> Lets first create a loopback adapter and give it a name internetconnection

Go to Start -->Run--->type hdwwiz.cpl (shortcut to hardware addition wizard) ---->Next

Select Yes I have already added the hardware and click next

select Add a new hardware device and click next

select install the hardware that i manually select from the list and click next

select Network adapters and then select Microsoft Loopback adapter and click next

Click Next and finish

Go to Start-->Run--->type ncpa.cpl and rename the loopback adapter to internet connection

2> Now that we have configured loopback adapter lets configure internet connection sharing to this loopback adapter from physical interface

Here I am sharing my wireless connection to loopback (But you can share your physical connection)

Go to Start--->Run----> ncpa.cpl and select your physical connection

Right click your physical connection and go to properties --- >Advanced ---> Select Allow other users to connect to internet through

this network interface --- > ok

3> Now goto GNS3

drag router 2691 and cloud to the console

Right click the cloud and goto to configuration

In the configurator node on the left select C1 and on the right in NIO ethernet tab select loopback adapter from list of available adapters and

click add and then click apply

Now from the top menu select Add a link and connect the cloud to routers fa0/0 interface

4>Right click the router and do start

Right click the router and go to console

now do the following ( note before going to below configuration if you are new to this site then please refer

my basic cisco device configuration section here Basic Cisco Device Configuration



R2>

R2>en

R2#config t

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

R2(config)#inter

R2(config)#interface fa

R2(config)#interface fastEthernet 0/0

R2(config-if)#ip address 192.168.0.2 255.255.255.0

R2(config-if)#no shutdown

R2(config-if)#exit

R2(config)#e

*Mar 1 00:00:54.611: %LINK-3-UPDOWN: Interface FastEthernet0/0, changed state to up

*Mar 1 00:00:55.611: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to up

R2(config)#exit

R2#ping

*Mar 1 00:00:57.211: %SYS-5-CONFIG_I: Configured from console by console

R2#ping 192.168.0.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.1, timeout is 2 seconds:

.!!!!

Success rate is 80 percent (4/5), round-trip min/avg/max = 20/26/32 ms

above we have given the ip 192.168.0.2/24 to router interface fastethernet 0/0 and we have connectivity to the clouds/loopback address ( remember to disable all the firewalls

and disble the antivirus because sometime antivirus will block network traffic)

Now lets try to ping to internet

R2#ping 8.8.8.8

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:

.....

Success rate is 0 percent (0/5)

above I have tried to ping 8.8.8.8 which is googles name server and it clearly shows that the ping is failing.

If we do R2#show ip route

Codes: C - connected, S - static, 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

i - IS-IS, su - IS-IS summary, 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 192.168.0.0/24 is directly connected, FastEthernet0/0

then the result clearly shows that the router only knows how to reach 192.168.0.0/24 network and any other netoworks the router doesnt know about.

So Now here we have to configure static routing on the router by doing

R2#config t

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

R2(config)#ip route 0.0.0.0 0.0.0.0 192.168.0.1 (This tells the router that to reach any network i.e 0.0.0.0/0.0.0.0 forward the packet to 192.168.0.1 and since we have shared our internet connection packets will be

forwarded to the internet

now check the router routing table, you wll find the newly added route

R2#show ip route

Codes: C - connected, S - static, 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

i - IS-IS, su - IS-IS summary, 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 192.168.0.1 to network 0.0.0.0

C 192.168.0.0/24 is directly connected, FastEthernet0/0

S* 0.0.0.0/0 [1/0] via 192.168.0.1

Now the ping will reach the destination

R2#ping 8.8.8.8

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 8.8.8.8, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 360/374/396 ms

you can also give name server to the router and ping using names like www.google.com by doing

R2(config)#ip na

R2(config)#ip nam

R2(config)#ip name-server 8.8.8.8

R2(config)#ip do

R2(config)#ip domain-loo

R2(config)#ip domain-lookup

R2(config)#exit

R2#ping

*Mar 1 00:11:04.923: %SYS-5-CONFIG_I: Configured from console by console

R2#ping www.google.com

Translating "www.google.com"...domain server (8.8.8.8) [OK]

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 74.125.235.17, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 344/349/372 ms

Thank you for being with me, we will meet you in my next post i.e RIP routing