Date: Thu, 13 Aug 1998 11:33:55 -0700 From: bmah@CA.Sandia.GOV (Bruce A. Mah) To: Jeremy Shaffner <jer@jorsm.com> Cc: freebsd-questions@FreeBSD.ORG Subject: Re: Traceroutes to Cisco Routers Message-ID: <199808131833.LAA25384@stennis.ca.sandia.gov> In-Reply-To: Your message of "Thu, 13 Aug 1998 10:21:14 CDT." <Pine.BSF.3.95q.980813091952.26137B-100000@mercury.jorsm.com>
next in thread | previous in thread | raw e-mail | index | archive | help
--==_Exmh_-1592123868P
Content-Type: text/plain; charset=us-ascii
If memory serves me right, Jeremy Shaffner wrote:
> When we do a traceroute from any FreeBSD machine (2.1.0-R, 2.2.1-R,
> 2.2.6-R) directly to the Cisco, the second of the three packets is
> *always* dropped (With no exceptions.) Traces carried *past* the Cisco
> are fine however.
>
> Traces run from other OS's are fine, it's just a FreeBSD/Cisco thing.
> Another ISP I'm friendly with also sees the exact same thing with their
> FreeBSD/Cisco(s) combo. (Theirs is a Cisco 450.)
Jeremy--
I just did a couple of quick experiments at my lab. In these, traceroutes
from a FreeBSD 2.2.7-RELEASE box to a Cisco 7500 (IOS 11.2(13)) are missing
the second of the three ICMP responses, as you saw. But so did traceroutes
run from a Sun Ultra 2 (Solaris 2.5.1), and an Alpha (OSF/1 3.2).
I bet the Cisco box has some kind of rate-limiting for ICMP packets. I seem
to remember that Solaris boxes do this too, tentatively confirmed by a couple
of traceroutes I just ran now. My gut feeling is that this isn't really a
FreeBSD problem, but perhaps someone else more knowledgeable can give an
authoritative answer.
Bruce.
PS. Why do traceroutes past the Cisco work fine? They're different ICMP
error messages ("TTL expired", as opposed to "port unreachable"), probably
generated by different codepaths in IOS.
--==_Exmh_-1592123868P
Content-Type: application/pgp-signature
-----BEGIN PGP MESSAGE-----
Version: 2.6.2
iQCVAwUBNdMxkqjOOi0j7CY9AQHeFgP/f1LfovUjISi6sSH9iC2iZXhlqlzBUqWN
xOK1infn0M7GNEQVlyCFxbwpFBaiEbiKoG2JLpi6FsvgZ8Ds4IGDIhhyAoB27g2I
OiyPf8LGl4GV/DU/OdMVDENvJIEwH+eMlMIm7cs/jv0IpjVoXezHEQ0mxGIY41vs
4mDuz2uZzok=
=6VEF
-----END PGP MESSAGE-----
--==_Exmh_-1592123868P--
To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-questions" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199808131833.LAA25384>