Section 6.3 of the following document describes this issue in detail and may help you solve it.
http://renaud.waldura.com/doc/freebsd/pppoe/ ----- Original Message ----- From: "Tom Samplonius" <[EMAIL PROTECTED]> To: "Mike Tancsa" <[EMAIL PROTECTED]> Cc: <[EMAIL PROTECTED]> Sent: Tuesday, June 18, 2002 3:09 PM Subject: Re: tracking down strange MTU issues with PPPoE) > > Well, if you need to find the MTU, the ppp logs should tell you what the > remote end is telling you to use. > > Usually, if you are having a MTU problem, it relates to fragmentation, > MTU detection and ICMP filters. FreeBSD uses MTU detection by default. > However, MTU detection requires that ICMP "can't fragment" messages be > received, and some broken sites filter all ICMP. I know that the Redback > has an "ignore don't fragment" feature. If this is enabled, it will > fragment packets, it would normally throw away. This feature will break > MTU detection too, but at least the end user won't notice, and packets > will flow. > > > Tom > > > On Tue, 18 Jun 2002, Mike Tancsa wrote: > > > > > The DSL whole supplier we use (Bell Canada) has been turfing their Redback > > SMSes and moving to an ERX from unisphere networks. > > > > With the Redback, all was great... I had a FreeBSD box acting as a NAT > > gateway for a number of Windows boxes and all was great. Then, the > > customer got moved over to one of these ERXes and there is now some strange > > MTU problem. Couple of things. Supposedly the default MTU on the ERX is > > 1472 (or 1452) depending on who you talk to and not 1492. > > > > e.g. when doing a fetch to > > >> lynx2.8.4rel.1.tar.bz2 doesn't seem to exist in /usr/ports/distfiles/. > > >> Attempting to fetch from http://lynx.isc.org/current/. > > Receiving lynx2.8.4rel.1.tar.bz2 (1940531 bytes): 0%^C > > 16682 bytes transferred in 89.5 seconds (186.41 Bps) > > fetch: transfer interrupted > > > > Notice the speed... Its totally brutal. yet, a transfer from just a few > > hops away is fine. > > > > My question is, how can I track this problem down ? There seems to be some > > strange interaction with FreeBSD because if I put a Windows box on the > > other end, it does not suffer from this same problem. I can easily repeat > > the problem, but the question is, how can I track down the issue and then > > explain it to my telco. To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-net" in the body of the message
