From owner-freebsd-net Sun Mar 5 14:17:58 2000 Delivered-To: freebsd-net@freebsd.org Received: from awfulhak.org (tun.AwfulHak.org [194.242.139.173]) by hub.freebsd.org (Postfix) with ESMTP id D361F37BB2D; Sun, 5 Mar 2000 14:17:40 -0800 (PST) (envelope-from brian@Awfulhak.org) Received: from hak.lan.Awfulhak.org (root@hak.lan.awfulhak.org [172.16.0.12]) by awfulhak.org (8.9.3/8.9.3) with ESMTP id WAA04854; Sun, 5 Mar 2000 22:13:45 GMT (envelope-from brian@hak.lan.Awfulhak.org) Received: from hak.lan.Awfulhak.org (brian@localhost [127.0.0.1]) by hak.lan.Awfulhak.org (8.9.3/8.9.3) with ESMTP id WAA07676; Sun, 5 Mar 2000 22:13:39 GMT (envelope-from brian@hak.lan.Awfulhak.org) Message-Id: <200003052213.WAA07676@hak.lan.Awfulhak.org> X-Mailer: exmh version 2.1.1 10/15/1999 To: Brian Somers Cc: Dermot McNally , Dermot McNally , freebsd-net@FreeBSD.org, peter@FreeBSD.org, jkh@FreeBSD.org, joe@FreeBSD.org, brian@hak.lan.awfulhak.org, brian@hak.lan.awfulhak.org Subject: Re: NAT issues with ppp - a fix In-Reply-To: Message from Brian Somers of "Sun, 05 Mar 2000 03:49:23 GMT." <200003050349.DAA03010@hak.lan.Awfulhak.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sun, 05 Mar 2000 22:13:39 +0000 From: Brian Somers Sender: owner-freebsd-net@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org > > > At 02:18 04.03.2000 +0000, Brian Somers wrote: > > > >Hi, > > > > > > > >Because of a recent change in the way I connect to the net > > > >(PPPoUDPoPPPoISDN), I'm now seeing this problem ! > > > > > > > >Can you try the attached patch ? I believe this fixes the problem ! > > > > > > Bad news on my side - it doesn't appear to have helped. My test case: > > > Before applying the patch, I cvsupped to today's current and rebuilt the > > > world. Then I set the gateway box and a FreeBSD alpha box on my internal > > > network back to an MTU of 1500. I connected to confirm that the problem was > > > still there (it was). > > > > > > Then I applied the patch, rebuilt and installed ppp. Same test. Same > > > problem - well, same symptoms anyway. My two tests were, using Lynx to > > > connect to effectively any WWW site and using fetch to download a biggish > > > file. Fetch determines the file size (which I don't recall it managing to > > > do before), but doesn't actually get any further with the download. Lynx > > > manages to look up the site to which I try to connect, but then hangs at > > > the "waiting for response" stage. > > > > > > I can packet sniff this if you think it will help - my setup is slightly > > > different to yours: PPPoE via a DSL "modem". > > > > Mine is even more tricky... I've been battling this for some time > > now. > > > > I've actually got > > > > laptop -ethernet-gate-PPPoUDPoPPPoISDN- - PPPoISDN gateway - 'net - - PPPoUDP gateway - 'net > > > > The tricky bit is that I have to run the PPPoUDP link in MP mode using > > a 1466 byte MRRU. This will make the IP layer fragment the traffic to > > 1466 bytes, allowing ppp to pile a UDP/IP header of 28 bytes back on > > the front (and to add the 2/4 byte MP header and 1/2 byte protocol > > header) before sending out the UDP datagram. > > > > It's vital that the PPP/UDP/IP packet is no more than 1500 bytes as > > it's going to pop up at my gateway and then must travel across the > > 'net to the PPP/UDP gateway before it's unpacked and reassembled into > > what was sent out originally. > > > > I *think* this should work now - assuming the fragmentation side of > > things is functional. I haven't proven things yet though. > > > > I'll follow up.... > [.....] > > This works (with the previous patch), but requires an MRRU of > 1338.... as there can be up to 128 bytes of options (is this right > anyone ?). > > This means three things. First, I get to play with doing MP over two > separate ISPs for real (soon). Second I get a compressed ISDN link > with a static IP despite the transport being brought up and down with > dynamic IP numbers :*P > > And third, your problem must be something specific to PPPoE as it > looks like there are no NAT/fragmentation problems any more > (otherwise my setup can't work). > > I guess I'm gonna have to try to set up a proper PPPoE environment > here. I'll follow-up when I can. Hmm, I take that back. I'm still having problems. The problems can be circumvented with an MRU/MTU of 1000 and an MRRU of 1500 - causing ppp to set the iface to 1500 and chop the results up into 1000 byte frames. This'll need more testing before I can even look at trying to reproduce something consistently :-/ -- Brian Don't _EVER_ lose your sense of humour ! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message