>>> ip a s | grep mtu
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
2: eth1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast master vzbr1 state UP group default qlen 1000
3: eth2: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
4: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
5: ifb0: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 32
6: ifb1: <BROADCAST,NOARP> mtu 1500 qdisc noop state DOWN group default qlen 32
7: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
8: vzbr1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1396 qdisc noqueue state UP group default qlen 1000
11: vethN0ORC6@if10: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP group default qlen 1000
13: veth9DRC1U@if12: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP group default qlen 1000
15: vethBBCR8T@if14: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue master br0 state UP group default qlen 1000
16: gre0@NONE: <NOARP> mtu 1476 qdisc noop state DOWN group default qlen 1000
17: gretap0@NONE: <BROADCAST,MULTICAST> mtu 1476 qdisc noop state DOWN group default qlen 1000
18: erspan0@NONE: <BROADCAST,MULTICAST> mtu 1464 qdisc noop state DOWN group default qlen 1000
19: gretap1@NONE: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1396 qdisc pfifo_fast master vzbr1 state UNKNOWN group default qlen 1000
25: wg0: <POINTOPOINT,NOARP,UP,LOWER_UP> mtu 1420 qdisc noqueue state UNKNOWN group default qlen 1000