Hi Robie, Let me answer your questions:
> Why is br0 being set up to bridge eth0? Is something doing this automatically > or is this configuration necessary for something (if so, what?)? This configuration (br0 on a single physical interface) is automatically generated by deploying openstack Juno (I don't know what particular component does it, atm) on Trusty. In our case it's not necessary/mandatory, but just the result of the installation. I don't know what consequences we might face by disabling/removing br0, though. > Without using br0 and just using plain eth0, does the interface-mtu option > work correctly? Will do asap, but on a first guess I think it would work >... If so, I'm not sure it really makes sense for the DHCP client to set the >MTU on eth0 when receiving DHCP over br0. I suppose it depends on the use case >though. I agree. In this particular scenario, having just one physical interface sharing its mac address with the bridge, I think it makes sense to expect the interface's MTU being set (there's no other interface acting as a constraint). Other situations, with several interfaces, manual config might be mandatory. -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to isc-dhcp in Ubuntu. https://bugs.launchpad.net/bugs/1403955 Title: DHCP's "Option interface-mtu 9000" is being ignored on bridge interface br0 Status in isc-dhcp package in Ubuntu: New Bug description: In an env with jumbo frames enabled, and using MAAS as DHCP server, the client receives the following IPv4 lease: $ cat /var/lib/dhcp/dhclient.br0.leases lease { interface "br0"; fixed-address 10.230.20.26; filename "pxelinux.0"; option subnet-mask 255.255.248.0; option dhcp-lease-time 43200; option routers 10.230.16.1; option dhcp-message-type 5; option dhcp-server-identifier 10.230.20.1; option domain-name-servers 10.230.20.1; option interface-mtu 9000; option broadcast-address 10.230.23.255; option domain-name "ctsstack.qa.1ss"; renew 3 2014/12/17 16:48:15; rebind 3 2014/12/17 21:52:09; expire 3 2014/12/17 23:22:09; } The interfaces show the following config after boot: $ ifconfig br0 br0 Link encap:Ethernet HWaddr a0:d3:c1:01:9d:58 inet addr:10.230.20.26 Bcast:10.230.23.255 Mask:255.255.248.0 inet6 addr: fe80::a2d3:c1ff:fe01:9d58/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:530530 errors:0 dropped:0 overruns:0 frame:0 TX packets:1591569 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:68713489 (68.7 MB) TX bytes:213710979 (213.7 MB) $ ifconfig eth0 eth0 Link encap:Ethernet HWaddr a0:d3:c1:01:9d:58 inet6 addr: fe80::a2d3:c1ff:fe01:9d58/64 Scope:Link UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1 RX packets:10539274 errors:0 dropped:3394 overruns:0 frame:454 TX packets:2627412 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:1000 RX bytes:2320560616 (2.3 GB) TX bytes:3562885157 (3.5 GB) Interrupt:32 "option interface-mtu 9000;" from the lease file is being ignored by br0. Could it be related to eth0 MTU size? If that's the case, shouldn't both interfaces be updated? Other info: $ brctl show br0 bridge name bridge id STP enabled interfaces br0 8000.a0d3c1019d58 no eth0 $ cat /etc/network/eth0.config iface eth0 inet manual auto br0 iface br0 inet dhcp bridge_ports eth0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/isc-dhcp/+bug/1403955/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
