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ICMP debug on Cisco Router

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by ngunity

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Basic question, but one that has me confused:

I've been debugging IP ICMP on one of my routers: router2, router1 is the internet gateway and router2 sits between router1 and my firewall, i.e. Internet>Router1>router2>firewall>LAN
the Firewalls only gateway is router2 and router2's only gateway is router1.

I have been running a ping from the internet to the firewall, and another back out from the firewall to the internet and been debugging traffic on router2.

router2 shows traffic thatsays:
ICMP: redirect sent to for dest , use GW

Does this debug show incoming pings from the internet?? I.e. is it showing that it is redirecting traffic to for , if so why does it mention ?

basically I want to know what 'redirect sent to', 'for dest' and 'use gw' mean in the ICMP debug?

3 replies

by mbatty

What this means is that Router2 is telling the Firewall that there is a more direct route via router1.

This is problably due to router2 thinking that the firewall can talk directly to router1. difficult to devine why that would be without full knowledge, but it could be that hop counts are not being incremented as there is no routing protocol running OR it may be that both router1 and router2 are directly addressable by the firewall (i.e. not wired up as you think it is).

by ngunity

There is a direct path and yes according to Cisco this is what the router is telling me. It was driving me nuts and causing way to many logs incidentally so I turned off redirect notification

thanks

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