There is a program that intercepts tcp session negotiation and
artificially reduces the negotiated MTU but I can't find it right now..
I think it was called mssd or something.


On Mon, 4 Nov 2002, Agent Drek wrote:

> On Mon, 4 Nov 2002, Steve Francis wrote:
> 
> > Date: Mon, 04 Nov 2002 09:00:47 -0800
> > From: Steve Francis <[EMAIL PROTECTED]>
> > To: Agent Drek <[EMAIL PROTECTED]>
> > Cc: "[EMAIL PROTECTED]" <[EMAIL PROTECTED]>
> > 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
> 
> 
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