[30145] in North American Network Operators' Group
Re: Path-MTU-discovery
daemon@ATHENA.MIT.EDU (Mikael Abrahamsson)
Mon Jul 17 02:28:27 2000
Date: Mon, 17 Jul 2000 08:26:10 +0200 (MEST)
From: Mikael Abrahamsson <swmike@swm.pp.se>
To: North America Network Operators Group Mailing List <nanog@merit.edu>
In-Reply-To: <20000716215914.DB9FD87@proven.weird.com>
Message-ID: <Pine.LNX.4.10.10007170821120.30477-100000@uplift.swm.pp.se>
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On Sun, 16 Jul 2000, Greg A. Woods wrote:
> Experience is beginning to suggest that it's the vast majority of them
> that use PMTUd now. Where it doesn't work _at_all_ on the "client" side
> you quickly find out that perhaps as many as 2/3's (anecdotally
> measured) of the "popular" web servers out there seem to be unusable
I am behind a tunnel with something like 1446 MTU. It works just nicely, I
have not found any sites so far that won't work.
On the other hand, at work we're doing some tunneling using ciscos. Due to
routing etc the ICMP "need-to-frag"-messages get lost and the people
behind those tunnels cannot use 90% of the www sites (so they have to
resort to proxies). Seems to me that PMTUd works better than most people
think.
I do believe that NT and Win2k comes default with a registry setting that
makes it send all TCP traffic with the DF flag set (which I can see no
reason for unless M$ IP stack cannot do refragmentation properly). This
setting is changable as far as I know but I cannot seem to find the
information at this time. Anyone?
--
Mikael Abrahamsson email: swmike@swm.pp.se
