Subject: Re: SOLVED! The cause of puzzling TCP (eg. WHOIS) connection failures with some InterNIC.net hosts
To: NetBSD Networking Technical Discussion List <tech-net@netbsd.org>
From: Greg A. Woods <woods@most.weird.com>
List: tech-net
Date: 11/22/1998 12:57:17
[ On Sat, November 21, 1998 at 21:41:25 (-0500), Perry E. Metzger wrote: ]
> Subject: Re: SOLVED! The cause of puzzling TCP (eg. WHOIS) connection failures with some InterNIC.net hosts 
>
> Greg, this is an IETF issue,

Yes.

>    not a NetBSD issue. We're doing what we
> need to.

Wrong.

There are many places where NetBSD (and/or 4.4bsd in general) slips away
from full compliance with RFCs when it can do something better (or
sometimes when it's lazy).  Leaving broken PMTUD in place even when we
know about it, and when we can safely do something about it, is a
seriously bad cop-out.

>   Firewall and NAT vendors are starting to figure out that they 
> can't be lazy about this.

Hopefully they are, but I've not seen any evidence of the fact (not that
I pay extremely close attention to the latest & greatest things from all
firewall *vendors*).

(Individual firewall administrators are starting to learn....)

> The problem is not ours and will correct
> itself.

Not for a long, long, time, and unless the IETF does do something about
it (in the form of an RFC1191bis or similar) then there will always be a
flaw in the protocol which can cause TCP connections to fail without
warning and without any means of one end discovering the cause in an
isolated situation.  If NetBSD can provide a proven solution to the
problem at the router and PMTUD server level (for lack of a better term)
then we can set a good example that others can follow.

-- 
							Greg A. Woods

+1 416 218-0098      VE3TCP      <gwoods@acm.org>      <robohack!woods>
Planix, Inc. <woods@planix.com>; Secrets of the Weird <woods@weird.com>