nanog mailing list archives

Re: ICMP Blocking Woes


From: "Kevin Oberman" <oberman () es net>
Date: Wed, 01 Oct 2003 10:32:21 -0700


Date: Tue, 30 Sep 2003 19:36:23 -0500
From: John Kristoff <jtk () depaul edu>
Sender: owner-nanog () 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 () es net                       Phone: +1 510 486-8634


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