Date: Mon, 4 Nov 2002 13:07:38 -0500 (EST) From: Agent Drek <drek@smashpow.net> To: Steve Francis <steve@expertcity.com> Cc: "net@freebsd.org" <net@freebsd.org> Subject: Re: MTU problems ... Message-ID: <Pine.BSF.4.44.0211041259540.79976-100000@bang.smashpow.net> In-Reply-To: <3DC6A7BF.7010209@expertcity.com>
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On Mon, 4 Nov 2002, Steve Francis wrote: > Date: Mon, 04 Nov 2002 09:00:47 -0800 > From: Steve Francis <steve@expertcity.com> > To: Agent Drek <drek@smashpow.net> > Cc: "net@freebsd.org" <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
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