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Community Member

Help with 2600 router and gateway

I have 2 2600 series routers each on one end of a point to point T1. Lets call them router A for main office router and router B for the branch office. I have a very basic configuration, and a static route on each router pushing traffic to the other router. At the main site we have dsl connection for the internet and a snapgear 580 firewall which acts as our gateway. I can ping anything at Site B from Site A without any problems, but pinging from Site B to site A the ping stops at the ethernet port on router A . I know its a gateway issue I can change a pc's gateway to the lan port on Router A and the ping is succesful, the only problem with that I need the snapgear to be the gateway. for example.

Router A

Serial interface 192.168.1.1

ethernet interface 10.0.0.1

ip route 10.0.1.0 255.255.255.0 192.168.1.2

Router B

serial interface 192.168.1.2

ethernet interface 10.0.1.1

ip route 10.0.0.0 255.255.255.0 192.168.1.1

also have a route on the 580

all traffic going to 10.0.1.0 go through 10.0.0.1

any help would be appreciated thanks

7 REPLIES
Hall of Fame Super Gold

Re: Help with 2600 router and gateway

Ross

Given what you have posted it looks to me like the problem is the lack of a default route on router B. I think the lack of a default route on router A is also problematic, but not part of your issue about pinging from router B.

HTH

Rick

Community Member

Re: Help with 2600 router and gateway

Since I posted earlier I have removed the route from Router B and added ip route 0.0.0.0 0.0.0.0 192.168.1.1

I am still having trouble with the ping. I know I am missing something simple.

Thanks

Ross

Hall of Fame Super Gold

Re: Help with 2600 router and gateway

Ross

Lack of default route on router B was certainly a problem. Have you also provided a default route on router A?

It might be helpful if you would post the output of show ip route from router B and the output of show ip route from router A.

It might also be helpful to get a restatement of the problem (what works and what does not work). For example:

PC configured with IP address , mask , gateway

can ping to ?

can not ping to ?

HTH

Rick

Community Member

Re: Help with 2600 router and gateway

Thanks again for your help.

I do not have a default route on Router A

here is the show ip route results.

Router A

Gateway of last resort is not set

10.0.0.0/24 is subnetted, 2 subnets

C 10.0.0.0 is directly conected, Fastethernet0/0

S 10.0.1.0 is directly connected, Serial0/0:1

C 192.168.1.0/24 is directly connected, Serial0/0:1

Router B

Gateway of last resotr is 192.168.1.1 to network 0.0.0.0

10.0.0.0/24 is subnetted, 1 subnets

c 10.0.1.0 is directly connected, FastEthernet0/0

c 192.168.1.0/24 is directly connected, Serial0/0

s* 0.0.0.0/0 [1/0] via 192.168.1.1

Network on site A is 10.0.0.0 for example

PC A

IP address 10.0.0.240

Mask 255.255.255.0

Gateway 10.0.0.254 (snapgear 580)

This set up can ping to any address on the 10.0.1.0 network for example

PC B

ip address 10.0.1.2

mask 255.255.255.0

gateway 10.0.1.1 (Router B)

If I try to ping from Router B to PC A (10.0.0.240) I get no reply. But if I modify PC A to

ip address 10.0.0.240

mask 255.255.255.0

gateway 10.0.0.1 (Router A)

I get the ping request successful

I have a route set up in the snapgear 580 directing all 10.0.1.0 traffic to Router A (10.0.0.1)

With the gateway configured as the snapgear (10.0.0.254) I cannot ping past 10.0.0.1 interface on router A

Thanks again for your suggestions and help

Ross

Hall of Fame Super Gold

Re: Help with 2600 router and gateway

Ross

Thanks for the additional information. I am a bit puzzled by part of the explanation. First you say that:

PC A

IP address 10.0.0.240

Mask 255.255.255.0

Gateway 10.0.0.254 (snapgear 580)

This set up can ping to any address on the 10.0.1.0 network for example

but then you say that with this setup that router B ping to PC A fails.

Are you saying that with the gateway of PC A set to snapgear that PC a can ping router B but that router B can not ping PC A?

I have just drawn out the topology that you describe and that leads me to another question:

with the gateway of PC A set to snapgear can PC A ping to PC B? You report that PC A fails to ping router B but have not said whether it can ping PC B.

I am guessing that PC A can ping PC B but not router B. That leads me to the theory that the problem is that snapgear has a route to the Ethernet of router B but does not have a route for the serial interface that connects the routers. It would be the serial interface address that is used if router B attempts to ping PC A. Try adding a route in snapgear for network 192.168.1.0 and see if that resolves the problem.

HTH

Rick

Community Member

Re: Help with 2600 router and gateway

Sorry for the confusion ..

Are you saying that with the gateway of PC A set to snapgear that PC a can ping router B but that router B can not ping PC A? Yes that is correct PC A can ping anything on the 10.0.1.0 (lets say Network B) network.

PC A can ping router B and anything on network B with the snapgear as the gateway or with Router A as the gateway.

I am not at the site with PC B so I am telneting to router B and pinging from there. I get no respose to pings from router B going to PC A using the snapgear as a gateway. But, if I use Router A as the gateway the ping works fine.

I have full connectivity from Network A (10.0.0.0) network to Network B (10.0.1.0) But From Network B to Network A I only have connectivity if I use Router A as the gateway for Network A, But I need the gateway to be snapgear 580. and again I am sorry for the confusion working on this I have almost confused myself.

I added the 192.168.1.0 route in the snapgear and I end up with the same result.

Thanks again for your help, I really appreciate your suggestions and time.

Hall of Fame Super Gold

Re: Help with 2600 router and gateway

Ross

Lets take a slightly different approach: with the gateway of PC A set to snapgear then from router B do a standard ping to PC A (which should fail) and then do an extended ping from router B to PC A and in the extended ping specify the source address of the ping as the Ethernet interface of router B.

I am guessing that the standard ping which uses the serial interface as the source address will fail but that the extended ping which uses the LAN interface as the source may succeed.

Give this a try and let us know what happens.

HTH

Rick

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