Date: Fri, 29 Mar 2019 23:04:19 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 236888] ppp daemon limits mtu to 1492 for PPPoE Message-ID: <bug-236888-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D236888 Bug ID: 236888 Summary: ppp daemon limits mtu to 1492 for PPPoE Product: Base System Version: 11.2-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: bin Assignee: bugs@FreeBSD.org Reporter: freebsd.68fba@nospam.spacesurfer.com The ppp daemon in FreeBSD 11.2 limits the maximum MTU to 1492 for the ppp/t= un device. Changing the MTU and MRU in the ppp.conf file to values above 1492 doesn't work. This is because the limit is hard coded in /usr/src/usr.sbin/ppp/ether.c My ADSL modem (vigor 130) supports an MTU above 1500 and if I change the li= mit in ether.c to 1500, set my ethernet mtu to 1508 or more, then ppp will negotiate a higher MTU/MRU for the link and it will work fine (I tried 1500 byte ping probes with the DF flag set and it works) Unfortunately, you can't just change the ether.c value because it uses the limit as the default and so my old modem (can only do 1492 or less) will not work unless I set the MTU to 1492 in the ppp.conf file. It would probably be best to leave the default at 1492 since this is the most common maximum MTU= for ADSL modems, but allow it to be overridden to whatever you want in the conf= ig file. --=20 You are receiving this mail because: You are the assignee for the bug.=
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