[ On Sun, November 22, 1998 at 13:07:39 (-0800), Kevin M. Lahey wrote: ]
> Subject: Re: SOLVED! The cause of puzzling TCP (eg. WHOIS) connection failures with some InterNIC.net hosts 
>
> Perhaps we could come up with a way to force the NetBSD system to
> send a small MSS (536 was the pre-PMTUD default) you'd be able to 
> ensure that the other side would send reasonable packets.

That's exactly what I was trying to suggest.  The trick is to do this
only when necessary.  In general I do see enough advantage to using a
larger MSS, especially for local network traffic, and even 536 is just
more than half what my PPP link permits.

> It still seems stunningly lame for a site to turn on PMTUD when it
> is behind firewalls that default PMTU!  Yeesh.

There's often a surprisingly large gap in the communications between the
groups that run the firewalls and the groups that run the servers inside
of an organization.  The inside guys will have just as hard a time as I
did, or harder, in determining the cause of the failure if they can't do
a tcpdump on the outside of the firewall, and in some environments I've
worked doing that would be flatly impossible.

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods@acm.org>      <robohack!woods>
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