From owner-freebsd-questions Thu Aug 13 16:39:57 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id QAA11041 for freebsd-questions-outgoing; Thu, 13 Aug 1998 16:39:57 -0700 (PDT) (envelope-from owner-freebsd-questions@FreeBSD.ORG) Received: from stennis.ca.sandia.gov (stennis.ca.sandia.gov [146.246.243.44]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id QAA11023 for ; Thu, 13 Aug 1998 16:39:44 -0700 (PDT) (envelope-from bmah@stennis.ca.sandia.gov) Received: (from bmah@localhost) by stennis.ca.sandia.gov (8.9.1/8.9.1) id QAA29004; Thu, 13 Aug 1998 16:39:05 -0700 (PDT) Message-Id: <199808132339.QAA29004@stennis.ca.sandia.gov> X-Mailer: exmh version 2.0.2 2/24/98 To: Jeremy Shaffner Cc: "Joe \"Marcus\" Clarke" , freebsd-questions@FreeBSD.ORG Subject: Re: Traceroutes to Cisco Routers In-Reply-To: Your message of "Thu, 13 Aug 1998 17:41:07 CDT." From: bmah@CA.Sandia.GOV (Bruce A. Mah) Reply-To: bmah@CA.Sandia.GOV X-Face: g~c`.{#4q0"(V*b#g[i~rXgm*w;:nMfz%_RZLma)UgGN&=j`5vXoU^@n5v4:OO)c["!w)nD/!!~e4Sj7LiT'6*wZ83454H""lb{CC%T37O!!'S$S&D}sem7I[A 2V%N&+ X-Url: http://www.ca.sandia.gov/~bmah/ Mime-Version: 1.0 Content-Type: multipart/signed; boundary="==_Exmh_-389640468P"; micalg=pgp-md5; protocol="application/pgp-signature" Content-Transfer-Encoding: 7bit Date: Thu, 13 Aug 1998 16:39:05 -0700 Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG --==_Exmh_-389640468P Content-Type: text/plain; charset=us-ascii If memory serves me right, Jeremy Shaffner wrote: > On Thu, 13 Aug 1998, Joe "Marcus" Clarke wrote: > > Cisco throttles ICMP unreachables so that only 2 unreachables per second > > are sent. The result puts a star in one of the fields: > > > > i.e. (200 ms) (200 ms) * Whew, I guessed right! :-) > Fair enough. But it's dropping the second and not the third. > > And it doesn't explain why non-Unix OS's trace to it fine. I can't speak for MacOS, but the Win95 tracert command uses ICMP echo requests (just confirmed via tcpdump), while all of the UNIX traceroute programs use UDP packets to arbitrary, high-numbered UDP ports. Presumably the Cisco IOS doesn't rate-limit ICMP echo replies in the same way that it does ICMP echo requests. (In an earlier message, you asked if the UNIX traceroutes all shared a common code base, and AFAIK the answer is "yes".) Bruce. --==_Exmh_-389640468P Content-Type: application/pgp-signature -----BEGIN PGP MESSAGE----- Version: 2.6.2 iQCVAwUBNdN5GKjOOi0j7CY9AQEi3QP+Nxz0EbzC3njFyVrJRu4D9tPN5+iv2OcN Oi+ixqBh95JJl+eo5Vz7lEF3fpMg+E6DoYT2/Pv7seqsBRmHl627elOOuBUk/T+C +zy2fZUGQE/QPlCgGOCqEJnLlMhJeVTEGxHS+0z3mTT2Zc2TDo6R2L1P5pHpyHam WJxJAqSn8fA= =ZYzq -----END PGP MESSAGE----- --==_Exmh_-389640468P-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message