https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292760
--- Comment #2 from [email protected] --- Sounds as wrong assumption for me - MTU is L3 maximum transmission unit size, 802.1Q header is L2 header, why it should affect MTU then? let me assume that bridge handles both tagged and untagged frames: # ifconfig bridge1 create mtu 1500 192.168.0.1/24 up # ifconfig bridge1.1 create 192.168.1.1/24 up # ifconfig bridge1.1 bridge1.1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> metric 0 mtu 1496 options=0 ether 58:9c:fc:10:e2:e3 groups: vlan vlan: 1 vlanproto: 802.1q vlanpcp: 0 parent interface: bridge1 nd6 options=29<PERFORMNUD,IFDISABLED,AUTO_LINKLOCAL> in that case I CANNOT use either bridge1 (untagged) or bridge1.1 (tagged) with correct MTU (1500) if I'll set 1504 on bridge1 -> my packets sent from 192.168.0.1 will be fragmented later on (as most of the internet is not capable to process frames more then 1500) if I'll set 1500 on bridge1 -> bridge1.1 will have MTU 1496 and normal frames forwarded via bridge1.1 will be unexpectedly fragmented. As I understanded -> vlanmtu flag should tell inteface that any VLAN headers should not be accounted in MTU calculations. -- You are receiving this mail because: You are the assignee for the bug.
