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Routing and Traceroute problems



I have a strange problem with a very simple network that has stumped me and hoping someone can shed some light. Probably a brain fade, but got me beat

Brief description

2 x 1720 routers connected via a frame.

Router A config :

F/E 0 =

Serial 0 =

F/E 0 connected to Cisco 2924 switch

Router A default gateway =

Router has RIP version 2 enabled with networks and being broadcast.

Router B config:-

F/E 0 =

Serial 0 =

F/E 0 connected to hub

Router default gateway =

Router has RIP version 2 enabled with networks and being broadcast.

Switch Config (located behind router A):-

Switch has IP address =

Switch default gateway =

Router A (via switch) workstation(s) config:-

default gateway = (to the switch)

Router B workstation config:-

Default gateways set to (have tried as well)

OK (apologies for the lengthy detail)

From Router B I can ping router A and workstations beyond Router A

From Router B I can traceroute to workstations behind router A and the switch, which is good. To my thinking there is a route to and from Router B through Router A, through the switch, to the workstation and then back again.

Problem is from Router A..(and anything behind router A)

I can ping workstations beyond Router B (via the hub), but I cannot traceroute to any devices behind Router B.

Im struggling to see what the reason is. I understand ping is different to traceroute, but I can FTP to the devices I am trying to traceroute to..weird...

Its causing some problems with an application we are running where comms are OK between Router B to A...but fail from Router A to B ( well, the devices behind router B ).

I can traceroute to each one of the routers..the problems happen when I try to get to devices beyond router B.

Confused!!?? I am just reading this, but hopefully someone will be able to help.

BTW, the workstations in question (behind router B) are running DOS and TCP/IP (PCTCP)

Any ideas folks???

Really appreciate any assistance...


3 Replies 3


Your pcs and switch should have the def. gw of their local router. Switch and pc's at site A should have as their gw. At B the gw should be


Hi Andrew,

U seems to be messed up in ur problem. Well..i m trying my hand in it...since i m a novice worker on routers and just got CCNA certified...cant say that my solution will really work for u...but still trying my hand to help u out.

Well...first of write "no auto-summary" command in config mode in both the routers. Then, check out the address of F/E port in Router A. I think...its not the right address to be mentioned...please check it out.

Hope this helps u...

Best of luck to u & me too...since this is the first time I m trying my hand





I think the switches default gateway is set wrong. SHould be and not 192.168.200. whatever.....

I`ll give this a whirl and see how it goes.

Strange though that if I can trace from one system to the other, but not the other way around. Surely if theres a path to and a return path from the device, then it works both ways...

Thanks very much guys...I`ll see how it goes