From owner-freebsd-net Mon Nov 4 10: 7:41 2002 Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E5BC737B401 for ; Mon, 4 Nov 2002 10:07:39 -0800 (PST) Received: from mail.smashpow.com (mail.smashpow.net [216.235.9.194]) by mx1.FreeBSD.org (Postfix) with ESMTP id 296E843E3B for ; Mon, 4 Nov 2002 10:07:39 -0800 (PST) (envelope-from drek@smashpow.net) Received: from mail.smashpow.net (mail.smashpow.net [216.235.9.194]) by mail.smashpow.com (Postfix) with ESMTP id 0762B21A; Mon, 4 Nov 2002 13:07:38 -0500 (EST) Date: Mon, 4 Nov 2002 13:07:38 -0500 (EST) From: Agent Drek To: Steve Francis Cc: "net@freebsd.org" Subject: Re: MTU problems ... In-Reply-To: <3DC6A7BF.7010209@expertcity.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On Mon, 4 Nov 2002, Steve Francis wrote: > Date: Mon, 04 Nov 2002 09:00:47 -0800 > From: Steve Francis > To: Agent Drek > Cc: "net@freebsd.org" > Subject: Re: MTU problems ... > > The problem below (which is still a problem in FreeBSD, but one that > will be rarely encountered) was caused by a load balancer in front of > the BSD boxes, that did not NAT part of the ICMP unreachable message > payload to the BSD's address. (The ICMP includes part of the original > datagram that caused the problem, and the load balancer did not > translate the sequence numbers, I think.) Its still a BSD problem (I'd > say) as if BSD hears the ICMP and reduces its MSS, it should not resend > the original packet at a size > MSS. > > So this could be your issue if your ISP is forcing all your traffic > through a proxy that does the same thing. > > A workaround would be disable PMTU-discovery. > hi, I didn't notice the pr until now: http://www.freebsd.org/cgi/query-pr.cgi?pr=42137 In my case the "load balancer" is something at the telco that is probably aggregating a bunch of stuff at the dslam. Thus I can't really fix the bad router, and there is no option of going somewhere else. I think I want something like: net.inet.tcp.stupid_router_in_front_of_me_mtu_hack->1 but that may not be what I need. Is it rude to send mail to that same pr? should I try and harvest more info first? disabling path mtu discovery just cause the problem to happen faster for me :( cheers, -- Derek Marshall Smash and Pow Inc > 'digital plumber' http://www.smashpow.net To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message