Ping Interface whithout route

Unanswered Question
Aug 16th, 2007

I have a Cisco 1812 with a c181x-advipservicesk9-mz.123-8.YI1.bin IOS, that is negotiating an internet pppoe connection through a bridge. It negotiates the public ip x.x.x.x, and in the router I have a route pointing the ip y.y.y.y to null0. When I try to ping the x.x.x.x from another internet connection y.y.y.y, it is reachable. It seems that any icmp traffic with destination my router interface (x.x.x.x) is sent in the same interface where it came in, and does not get routed. Any ideas.

I have this problem too.
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Pavel Bykov Fri, 08/17/2007 - 08:42

try using "terminal monitor" and "debug ip icmp" command to see where ICMP replies are sent.

Can you ping through the router (i.e. some internet address from some local network?)

Also, we need more information on your setup, it is not clear where the packets get lost.

y.y.y.y is the address of an outside network or an inside network? Is this a VPN between y.y.y.y and x.x.x.x ?

lliborio05 Mon, 08/20/2007 - 01:43

The y.y.y.y is an outside network, from other internet site. In my router i configure the route pointing y.y.y.y to null, and i still can ping, using the debug i see the packets sent to y.y.y.y.

If i ping the wan interface (x.x.x.x) from the lan of the router i got no responses. (i have no access-lists and no nat).

It seems that icmp packets sent to my wan interface are not routed, are just sent through the same wan interface.

IOS bug?


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