[nsp] RPF problem with ICMP unreachables

[Rajesh Talpade]

> 
> How does one force a router to not use *highest* IP address to return ICMP 
> unreachables and instead use the interface from where the ICMP came?

Wouldn't this be rather hard to do since ICMP messages are processed
inside the router's processing engine, and such ability requires keeping
state about what interface an IP packet arrived on?

Also, the path back to the ICMP originator may not be over the interface
that the ICMP arrived into the router, so what IP address would one
assign as the source of the ICMP unreachable?

Just a thought.

Rajesh.


> 
> -Hank