Date: Mon, 26 Nov 2001 21:27:40 -0500 From: "Matthew Emmerton" <matt@gsicomp.on.ca> To: "Julian Elischer" <julian@elischer.org> Cc: <freebsd-net@FreeBSD.ORG> Subject: Re: Very strange network behaviour - can anyone help me analyse tcpdump output? Message-ID: <006a01c176eb$172f6a20$1200a8c0@gsicomp.on.ca> References: <Pine.BSF.4.21.0111261802070.5212-100000@InterJet.elischer.org>
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> On Mon, 26 Nov 2001, Matthew Emmerton wrote:
>
> > Hi all,
> >
> > In the continuing saga of IPSec over PPPoE for a retail POS environment
that
> > I'm maintaing, the problems seem to become more complex as time goes on.
> >
> > The network is quite simple:
> > [ LAN #1 ] - [ FreeBSD Gateway #1 ] - [ ISP ] - [ FreeBSD Gateway #2 ] -
[
> > LAN #2 ]
> >
> > Both LANs connect using PPPoE with the same ISP, and are one hop apart
> > (according to traceroute).
> >
> > The problem is that a connection from the Internet (anywhere) to either
of
> > the FreeBSD gateways will "hang". Usually I can login but doing an
'ls -al'
> > will display a few lines of text and then nothing. This happens using a
> > bunch of telnet clients (Anzio on Win2K, Win2K and Win95 native,
FreeBSD)
> > from various ISPs, as well as *between* the gateways, so the problem is
most
> > definitely related to the ISP providing us service. However, they seem
to
> > think that it's our problem ("none of the customers that use Windows
have
> > this problem -- must be that Unix thing that you're using").
>
> If you are using gif, make sure it has a small MTU (try 512 bytes)
belmont.heers.on.ca# ifconfig gif0
gif0: flags=8011<UP,POINTOPOINT,MULTICAST> mtu 1280
inet 10.0.2.2 --> 10.0.2.130 netmask 0xffffffff
belmont.heers.on.ca# ifconfig gif0 mtu 512
ifconfig: ioctl (set mtu): Invalid argument
belmont.heers.on.ca# gifconfig gif0 mtu 512
gifconfig: mtu: bad value
belmont.heers.on.ca#
How am I supposed to change the MTU?
(These machines are running 4.3-RELEASE-p12)
--
Matt Emmerton
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