Subject: Re: ip_flow.c
To: Anders Magnusson <ragge@ludd.luth.se>
From: Christian E. Hopps <chopps@merit.edu>
List: tech-net
Date: 01/28/1999 00:05:10
Anders Magnusson <ragge@ludd.luth.se> writes:

> > On Wed, 27 Jan 1999 10:37:28 PST 
> >  Bill Fenner <fenner@parc.xerox.com> wrote:
> > 
> >  > 4.2.2.5 Header Checksum: RFC 791 Section 3.1
> >  >    
> >  >    As stated in Section [5.2.2], a router MUST verify the IP checksum of
> >  >    any packet that is received, and MUST discard messages containing
> >  >    invalid checksums.  The router MUST NOT provide a means to disable
> >  >    this checksum verification.
> > 
> > Well then, I guess that pretty much answers the question, eh? :-)
> > 
> Many router manufacturers don't cares about this; they just decrement
> TTL and increment checksum and forwards the packet.

Well if this is the case someone should write a new ID proposing
a modification to the above quoted RFC.  I'm not sure ``other
people do it'' is enough of a reason for us to do it also.

If we do decide to turn checksums off by default, I'd say we at
least allow the option (sysctl) to turn them back on.

Chris.