Re: different MTU on different VLAN's

On 01/10/2012, at 12:40, James Harper <james.harper@bendigoit.com.au> wrote:

I need it the other way around - eth0=1500, eth0.12=9000. I can't think of a reason why the hardware MTU couldn't be set to 9000 on the physical interface, but that Linux just doesn't send packets larger than 1500 on eth0.

that's the thing. eth0 is the physical interface, so it needs at least the MTU of any logical interface, plus vlan headers. when using vlans in Linux, I try to keep the physical interface free of IP and use it only as a vlan trunk. But I understand this isn't possible in all situations where you need tagged+untagged frames.