Helpon Pinging across Routers 1

[cbr1000]

I have connected a 1603 and a 1720 router by means of a DTE-DCE serial cable. I have also configured the IP address on the Ethernet and Serial port on both routers.

I can ping the ethernet port on the 1603 to which I have a network cable connected, but I cannot ping across this router to it's serial port or across the WAN to the 1720.

I am sure I have missed a part of the config but do not have the experience to know what.

Any help would be greatly appreciated, thanks in advance.

Martin

 

[ChrisAC]

It would help if you posted the configs.

"but I cannot ping across this router to it's serial port"

This sounds like your PC that is plugged into the ethernet port doesn't have a default gateway, therefore it can ping the ethernet interface (on the same network range) but not the routers serial interface (on a different network range).

Chris.


**********************
Chris A.C, CCNA, CCSA
**********************

 

[chieftan999]

You may need to post the config, but if you are using a DTE / DCE have you ensured that clocking has been set correctly?


Reamin positive. The affect on those around you will amaze.

 

[cbr1000]

Thank you for your responses, I will post the config of each router. A DCE-DTE cable is being used and the clock is set on the DCE side(1720).

I have managed to ping the serial port on the router the PC is connected to but, cannot ping across the WAN to the 1603.

Thanks again
Martin

 

[ChrisAC]

Can you ping across the WAN link from the routers? Can you see the MAC address of the other router from the first router? Does each router have a route to the LAN side of the other router?

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[cbr1000]

I have not set a static route, could you tell me the commands for this, please?

 

[ChrisAC]

ip route <dest-net> <netmask> <gateway>

So on router A you would need a route to network B via the serial address of router B (which router A can see via the serial link) and on router B you would need a route to network A via the serial address of router A.

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[cbr1000]

Thanks for your responses,

I have set the first router eth 0 to 192.168.2.100
first router serial 0 to 192.168.3.100

Second router Serial 0 to 192.168.4.100
Second Router Eth 0 192.168.5.100
I am adding a static route by
ip router 192.168.4.100 255.255.255.0 192.168.3.100

I get the following error:

%Inconsistent address and mask

Thanks
Martin

 

[chieftan999]

For the routers to communicate the Interfaces need to be on the same subnet and for security purposes this subnet is usually a /30 mask....for example look at the following:-

Router a - Serial 1 Interface = 192.168.3.5 255.255.255.252

The appropriate address at the other end of the link would be:-

Router b - Serial 1 Interface = 192.168.3.6 255.255.255.252

This uses the ONLY 2 available IP address in that particular range. The next available addresses would be 9 and 10 and then 13 and 14 (etc).

This should then allow you to ping across the 2 routers and allow connectivity.

Reamin positive. The affect on those around you will amaze.

 

[cbr1000]

i have set the serial interfaces to the above ip addresses.

Ethernet 0 on router A is 192.168.2.200
Ethernet 0 on router B is 192.168.4.200

I am entering the static route by :

ip route 192.168.3.6 255.255.255.252 192.168.2.200

and constantly get the error "%Inconsistent address and mask"

I have also tried:

ip route 192.168.3.6 255.255.255.0 192.168.2.200
ip route 192.168.3.6 0.0.0.252 192.168.2.200
ip route 192.168.3.6 255.255.255.252 192.168.3.5
ip route 192.168.3.6 0.0.0.252 192.168.3.5

And every other combination I can think of. Each tme i get "%Inconsistent address and mask", could you tell me where I am going wrong, please?

Many thanks for your help

 

[ChrisAC]

You are still getting the routes wrong. The routes should be TO the ethernet IP ranges (of the remote router) VIA the serial IP addresses, not to the serial addresses via the ethernet addresses.

Try this:

**********************************************************
Router A:

# clients on this network should have a default route of 192.168.2.100

ethernet0
ip address 192.168.2.200 255.255.255.0
!
serial0
ip address 172.16.10.1 255.255.255.252
!
# add a route to the remote network via the remote serial
ip route 192.168.4.0 255.255.255.0 172.16.10.2


**********************************************************

Router B:

# clients on this network should have a default route of 192.168.4.100

ethernet0
ip address 192.168.4.200 255.255.255.0
!
serial0
ip address 172.16.10.2 255.255.255.252
!
# add a route to the remote network via the remote serial
ip route 192.168.2.0 255.255.255.0 172.16.10.1

***********************************************************

So, each router should be able to ping each other via the 172.16.10.0 /30 link and each router should also be able to ping the remote ethernet address as each has a route to the remote network via the serial address of the other router (which it is directly connected to).

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************

 

[cbr1000]

Hi Chris

Problem sorted now, just wanted to thank you for your time, knowledge and patience.

Regards

Martin

 

[ChrisAC]

No problem. Happy New Year!

Chris.

**********************
Chris A.C, CCNA, CCSA
**********************