Change MTU Size on 10G NICs/VLANs

[spetrillo]

Hello all,

I have an Intel X550 2 port network adapter. I would like to change the MTU of the ports first, which in turn will allow me to change the MTU on the OPNsense interaces that are supported by this 2 port adapter. I have tested that ifconfig ix0 mtu 9000 works when I SSH to the firewall. Now I wanted this to persist through reboots and I added ifconfig ix0 mtu to the tunables section but it does not persist. I am back to 1500. Am I doing something wrong with this?

Thanks,
Steve

[pfry]

"Interfaces: [x550]" -> "Generic configuration" -> "MTU" doesn't do it? (I don't use an MTU >1500, so I don't care to try it.)

[spetrillo]

I am using vlans, so all my interfaces are the vlans themselves. Is there another way to amend it?

[pfry]

Ah, shoot. I didn't consider that the interface must be assigned. I have all of mine assigned, with my (one) VLAN main interface unconfigured. That is, the main interface is ixl3 (opt4), while the VLANs are opt9-opt17. It's a safe configuration (at least in my experience), but many folks prefer to leave the VLAN main unassigned.