From owner-freebsd-hackers Wed Dec 2 07:01:03 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id HAA01209 for freebsd-hackers-outgoing; Wed, 2 Dec 1998 07:01:03 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from ns.mt.sri.com (sri-gw.MT.net [206.127.105.141]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id HAA01202 for ; Wed, 2 Dec 1998 07:01:02 -0800 (PST) (envelope-from nate@mt.sri.com) Received: from mt.sri.com (rocky.mt.sri.com [206.127.76.100]) by ns.mt.sri.com (8.8.8/8.8.8) with SMTP id IAA07461; Wed, 2 Dec 1998 08:00:49 -0700 (MST) (envelope-from nate@rocky.mt.sri.com) Received: by mt.sri.com (SMI-8.6/SMI-SVR4) id IAA05468; Wed, 2 Dec 1998 08:00:48 -0700 Date: Wed, 2 Dec 1998 08:00:48 -0700 Message-Id: <199812021500.IAA05468@mt.sri.com> From: Nate Williams MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit To: Luigi Rizzo Cc: nate@mt.sri.com (Nate Williams), hackers@FreeBSD.ORG Subject: Re: TCP bug In-Reply-To: <199812020655.HAA01716@labinfo.iet.unipi.it> References: <199812011834.LAA00343@mt.sri.com> <199812020655.HAA01716@labinfo.iet.unipi.it> X-Mailer: VM 6.34 under 19.16 "Lille" XEmacs Lucid Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > > > just to understand, what is the problem related to ? > > > > The problem is related to the fact that I can't contact certain WWW > > machines from the 'internal ethernet' boxes. > > > > > TCP as you say in the Subject, or IP (routing), or firewall ? > > > Have you tried what happens by opening the firewall ? > > > > Yep, no difference. It appears my router box is not passing packets > > through to the boxes on the internal ethernet. I stuck the firewall on > > that box just to see if the TCP stack was getting the incoming packets, > > does a tcpdump on _both_ interfaces show anything interesting -- like > pkts coming in and then not going out ? Do they have something strange > (like some odd length, invalid checksums, IP options, etc.) which makes > the router act strangely ? Is there a correct return route > on the router box ? The original email had a tcpdump output on both interfaces. I can resend it if you like. I'm no tcpdump guru, so I was hoping someone else could help out. As far as routes, everything looks right, and almost all of my data gets through. It's just certain WWW sites that don't work. > > > > Any clues? A number of FreeBSD boxes in my net have this problem, so it > > > > would be nice to get this resolved. Note, I have Route-discovery ICMP > > > > > > btw: do the offending packets carry IP/TCP options by chance ? Just to > > > have an idea what to look at in the code. > > > > I have turned off TTCP if that's what you mean. The box in question > > no, i meant if the remote machine you are trying to contact is sending > you "unsolicited" IP options which make the router fail. Or, e.g., > they send pkts larger than the MTU of the receiver/outgoing interface > and with a "DF" flag set so the router has to dump the packet. ????? The only 'router' in question is my FreeBSD box. Again, I don't know how to read the output of tcpdump. Nate To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message