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Help with remote network router config

Hello people,

I need help getting hosts on my network to be able to access the internet via the following scenario:

Network A -- Router A -- Network B --- Router B

--- internet

Routers A and B are Cisco 1841 modular routers (similar to 1700 and

2600 series).

Router A is connected to Router B via serial link (X.21) Router B is connected to the internet via DSL WIC on dialer interface

Router A is the new router to the scenario to connect networks A and B together.

Hosts on network A can ping hosts on Network B. Hosts on network B can ping hosts on Network A. Hosts on network B can access internet (they always could). Hosts on network A CANNOT ping any address on the internet.

Router B is configured with NAT traffic to the internet and has had no problems delivering traffic to network B.

NAT access-list includes network A and network B.

Routers A and B are set up with RIP v1 running advertising networks A and B.

Router A was set with an "ip route 0.0.0.0 0.0.0.0 network B" to ensure

addresses not on networks in the routing table are delivered to Router B to pass on to the internet. I don't know if this is working as it should.

I ran a similar setup at home with a D-link router as the gateway and a

Cisco 2514 where Router A is here and had no problems.

I tried using "debug ip packet" and "debu ip icmp" on Router B to see what was getting through but nothing showed up when I tried to ping a known IP on the internet.

Any help and suggestions are appreciated. I think my main issue is identifying where my problem is with the right debug command. ie how do I follow a request from Network A to see what routers A and B are doing with the request (say a ping to a host on the internet).

Manbo.

Reply to
manbo
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Debug "ip packet detail" on router B. Debugging "ip icmp" will only show pings destined for router B's own interfaces. can you ping hosts in network A from router B? Does it have a route to network A?

BernieM

Reply to
BernieM

Thanks for your reply. RIP is enabled on both routers so the ip routing table on each router indicates each network. Hosts can ping each other on the different networks. The problem I am having is getting from hosts on the network B to get through to the internet via router A (hosts on network A have no problem getting to the internet).

Reply to
manbo

I'm c Hosts on network A can ping hosts on Network B. Hosts on network B can ping hosts on Network A. Hosts on network B can access internet (they always could). Hosts on network A CANNOT ping any address on the internet.

Now you're saying you can't get hosts from network B to get through to the internet via router A. Why would you? Doesn't the topology diagram show the Internet hanging off router B? ...

Network A -- Router A -- Network B --- Router B --- internet

BernieM

Reply to
BernieM

Thanks for your patience.

I came here to post the answer to my problem, which was a NAT issue.

Apologies for the mixup in my last post. The problem has been hosts on Network A not being able to reach the internet (via Router B).

Router B has been working for some time and NAT was enabled on the fastethernet port (ip nat inside) and the SHDSL interface (dialer 0 : ip nat outside). Routers A and B were connected via serial interfaces and what I did NOT do is enable NAT on Rotuer B's serial interface (ip nat inside). Once I picked up on this my problem seems to have been resolved.

Using debug ip packet detail didn't help much as I could not see anything on Router A indicating my test host on Network A was trying to get through to an external host address. I did manage to establish that Router A was successfully passing requests from hosts on Network A to Router B via a traceroute command on a host on Network B. The traceroute would indicate something like this:

1
Reply to
manbo

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