Can you explain which part fails? "ifupdown fails to set the device's mtu, which causes its attempt to set the ipv6 mtu to fail"
This is the change that drove the use of sysctl to set mtu: https://anonscm.debian.org/git/collab- maint/ifupdown.git/commit/?id=a1b2c5555fea935d91961dc2df3ac5cfe6668bcf which comes from bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=809714 and the tl;dr is that IPv6 supports per protocol, rather than interface. It appears that we want the opposite here; so it's not quite clear how to resolve this. In the case that the user doesn't want the underlying interface MTU to change, then the sysctl is needed to change the MTU *only* for IPv6. In the original bug where one is comparing ip output of MTU; is there something *not* working ? Or did we just observe that the bond interface isn't the same MTU? Can we confirm that without the bond interface itself set to MTU 9202 that we don't see the correct jumbo frames over ipv6? ** Bug watch added: Debian Bug tracker #809714 http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=809714 ** Changed in: ifupdown (Ubuntu) Status: Confirmed => Incomplete -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1609367 Title: ifupdown does not set ipv6-only large mtu To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/ifupdown/+bug/1609367/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs