ICMP Blocking Woes

Wed Oct 1 17:32:21 UTC 2003

> Date: Tue, 30 Sep 2003 19:36:23 -0500
> From: John Kristoff <jtk at depaul.edu>
> Sender: owner-nanog at merit.edu
> 
> 
> On Tue, Sep 30, 2003 at 05:22:25PM -0700, Crist Clark wrote:
> > > Wasn't this based upon the premise that gear should not return ICMP
> > > errors as a result of ICMP packet input as a precaution against error
> > > loops? ie said dodgy router did the _right_ thing?
> 
> > That would be disingenious. RFC1122 clearly lists which ICMP are error
> > messages,
> 
> The following from W. Richard Stevens' archive presents some additional
> insight:
> 
>   <http://www.kohala.com/start/papers.others/vanj.99feb08.txt>

But note the date of this (1988). Clearly, router vendors are handling
this much better today, in light of 1122. Today tracert almost works
as well as traceroute.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634