back to back 1841 routers serial T1 interface

[Abbondanza23]

Hello all, I am trying to set up my CCNA lab environment, and I have everything working well, including the crossover connections between my three 1841 routers (all interfaces are up, and line protocols are all up)

In regards to those connections, via serial WIC-1DSU-T1-V2 WAN Interface Cards, I am not able to ping any of those specific interfaces IP addresses from the router they are on, nor am I able to ping from one node on Network 1 (Router1) across to Network2 (Router2).

Am I missing something like OSPF, or some other protocol to get this last step to work?

Any help would be appreciated!

Regards,                                             

Jon

[Richard Burts · Accepted solution]

Jon

Good luck on your studies for CCNA. You should not need a protocol like OSPF for a router to ping a connected neighbor. You might need a routing protocol (or static routes) if you want to ping something that is not directly connected. If all interfaces show as up and with protocol showing as up that would seem like things should work and ping should work. But if it is not working then we need a bit more information from you to determine what is the issue. As a start would you post the output of show ip interface brief from each of the routers. It might also help if you would post the output of the command show cdp neighbor and of show cdp interface.

HTH

Rick

[Abbondanza23]

Rick,

Thanks so much for the quick response.  After reading your reassurance that if it's up it should respond to pings I scrutinized my configs and discovered that their were some inconsistencies.  I had put in some access lists to try to solve the problem Once I removed these entries, all interfaces are responding to pings across the links.

However, I still am unable to ping from R1 to a node that exists on a subnet of R2.

Do I need an access list or some type of translation to allow any traffic flowing from R1 to be allowed to traverse the link to R2 and to nodes it services? 

I guess my learning style is to receive a point in the right direction so I that I can then research how to do it, so I will retain the knowledge once I am successful.

Thanks again,

Jon

[Masoud Pourshabanian · Accepted solution]

Hello,

You need to configure route toward your subnets on both router.

Suppose

R1 subnet: 192.168.1.0/24  and R1 link 1.1.1.1

R2 subnet: 192.168.2.0/24 and  R2 link 1.1.1.2

On R1

Ip route 192.168.2.0 255.255.255.0 1.1.1.2

***********

On R2

Ip route 192.168.1.0 255.255.255.0 1.1.1.1

By default, traffic is allowed so you do not need to configure any access-list

Hope it helps,

Masoud

[Abbondanza23]

Masoud,

I was on that track and your advice told me I was on the right track.

Thanks much to you and Rick, I am now on to bigger and better problems to conquer!

Jon

[Masoud Pourshabanian]

Hello,

First rule: For any IPs on the router, you do not need to configure route statement. Route statement will be configured automatically.

second rule: On route statement, you need to configure the next hop.

ip route [destination] [mask] [nexthop]

ip route 192.168.4.0 255.255.255.0 fe0/0

fe0/0 is wrong here. Fe0/0 is not the next hop. S0/0/0 is the next hop.

Third rule: For point to point interfaces such as serial, for the next hop, you can set  either the interface or the next hop IP address while for broadcast interface such as ethernet, you should only set next hop IP address. So next hop IP address works any way.

If you share your configuration, I can take a look. Make sure your PC has default gateway which is the IP address of fa0/0.

Masoud

[Abbondanza23]

Thanks for the extra info, I worked it out!  Which is always the best way to learn, I think.

Regards,

Jon

[Masoud Pourshabanian]

You are most welcome. Practice makes perfect.

Masoud