[c-nsp] CPE with tracking redundancy and long lived (UDP) nat sessions

[Ivan Pepelnjak]

> After the routing and egress changes, the router should be well aware
> that continued traffic no longer matches the
> 
> ip nat inside source route-map ISPA Di1 overload
> 
> and now matches the
> 
> ip nat inside source route-map ISPB Di2 overload
> 
> for a simplistic example.
> 
> So the old translations are no longer valid with the new egress. They
> should be abandoned and new ones created.

Obviously the router does NOT check the "ip nat" rules if it gets a match in the NAT translation table. This behavior makes sense; if you'd change the NAT parameters of a live session, you'd lose the session anyway.

> And I would be quite happy clearing just the translations for the
> "wrong" global for all local inside translations, but syntax does not
> seem to allow that.

Write a Tcl script that does "show ip nat translations" and kills only the relevant ones ;)

Ivan Pepelnjak
blog.ioshints.info / www.ioshints.info