VLAN MTU not configured

[henri9813]

Hello,

My hypervisor has 2 nics:
- 1x 1Gb/s
- 1x 25Gb/s connected to a switch ( which lead to my upstream ).


I use OPNsense 24.7.12_2-amd64 in a XCP-NG virtual machine which has 4c / 8Gb ram / 50Gb nvme.

i'm in Hardware virtualization with paravirtualization drivers enabled (PVHVM) with Realtek 8139
i attached 2x the 25gb/s link ( 1 for wan, 1 for the local VLAN ).

I configured MTU 9000 on the two nics in opnsense.

All the vlans on my opnsense are configured in mtu 9000.

However, i don't understand why, but running ifconfig show:

Code Select Expand

xn1: flags=1008943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 9000
description: LAN (opt9)
options=503<RXCSUM,TXCSUM,TSO4,LRO>
ether 7a:10:c4:65:82:ca
inet6 fe80::7810:c4ff:fe65:82ca%xn1 prefixlen 64 scopeid 0x6
media: Ethernet manual
status: active
nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>
vlan0.1001: flags=1008943<UP,BROADCAST,RUNNING,PROMISC,SIMPLEX,MULTICAST,LOWER_UP> metric 0 mtu 1496
description: Hypervisors (opt1)
options=0
ether 7a:10:c4:65:82:ca
inet 10.255.1.254 netmask 0xffffff00 broadcast 10.255.0.255 vhid 1
inet6 fe80::7810:c4ff:fe65:82ca%vlan0.1000 prefixlen 64 scopeid 0x7
groups: vlan
carp: MASTER vhid 1 advbase 1 advskew 0
      peer 224.0.0.18 peer6 ff02::12
vlan: 1000 vlanproto: 802.1q vlanpcp: 0 parent interface: xn1
media: Ethernet manual
status: active
nd6 options=21<PERFORMNUD,AUTO_LINKLOCAL>

Do you know why ?



Thanks !