Date:        Tue, 12 Mar 2002 08:52:01 +0000
    From:        David Laight <david@l8s.co.uk>
    Message-ID:  <20020312085201.A2145@snowdrop.l8s.co.uk>

  | Routers don't have to touch anything beyond the ethernet MAC addresses
  | unless they have to do fragmentation or the route is being recorded.
  | (for IPV4 at least)

You mean aside from updating the TTL, and correcting the checksum,
dealing with source routes, router alerts, ...

The IP header is there for routing to use, that's its purpose.

kre