Public bug reported: 1. If the MTU of eth0 is 1500, network-manager fails to establish a pppoe connection, and the MTU of eth0 (not ppp0) is then automatically lowered to 1492. Now network-manager can successfully establish a pppoe connection. If I manually set the MTU of eth0 back to 1500, network- manager would fail again. See attached log.
2. The Access Concentrator of my ISP offers MTU values of both 1492 and 1442. pppd-2.4.5 in Ubuntu 14.04 adopts 1492 as the MTU of the ppp device, while pppd-2.4.7 in Xenial adopts 1442. Setting the lower MTU on the WAN link (ppp0) can easily cause PMTU-D problems, especially for remote VPN clients. ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: network-manager 1.0.4-0ubuntu9 ProcVersionSignature: Ubuntu 4.4.0-6.21-generic 4.4.1 Uname: Linux 4.4.0-6-generic i686 ApportVersion: 2.20-0ubuntu3 Architecture: i386 CurrentDesktop: LXDE Date: Sat Feb 20 09:56:32 2016 IpRoute: default via 172.16.10.1 dev eth0 proto static metric 100 169.254.0.0/16 dev eth0 scope link metric 1000 172.16.10.0/24 dev eth0 proto kernel scope link src 172.16.10.32 metric 100 NetworkManager.state: [main] NetworkingEnabled=true WirelessEnabled=false WWANEnabled=true RfKill: 0: phy0: Wireless LAN Soft blocked: yes Hard blocked: no SourcePackage: network-manager UpgradeStatus: Upgraded to xenial on 2016-02-19 (0 days ago) WpaSupplicantLog: nmcli-dev: DEVICE TYPE STATE DBUS-PATH CONNECTION CON-UUID CON-PATH eth0 ethernet connected /org/freedesktop/NetworkManager/Devices/1 Auto eth0 dff18f4d-6732-4eab-bd06-5209635b9bab /org/freedesktop/NetworkManager/ActiveConnection/11 irda0 unknown disconnected /org/freedesktop/NetworkManager/Devices/2 -- -- -- eth1 wifi unavailable /org/freedesktop/NetworkManager/Devices/3 -- -- -- lo loopback unmanaged /org/freedesktop/NetworkManager/Devices/0 -- -- -- nmcli-nm: Error: command ['nmcli', '-f', 'all', 'nm'] failed with exit code 2: Error: Object 'nm' is unknown, try 'nmcli help'. ** Affects: network-manager (Ubuntu) Importance: Undecided Status: New ** Tags: apport-bug i386 xenial ** Attachment added: "$ sed -n '/^Feb 20 08:45/,/^Feb 20 08:51/p' /var/log/syslog | egrep '(pppd|NetworkManager)' | sed 's/.../<username>/g; s/00:11:25:.../00:11:25:aa:bb:cc/g; s/ac:85:3d:../ac:85:3d:ee:dd:ff/g' > network-manager-pppoe.log" https://bugs.launchpad.net/bugs/1547754/+attachment/4576091/+files/network-manager-pppoe.log -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1547754 Title: pppoe MTU problems To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/network-manager/+bug/1547754/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs