```
# tcpdump -eni ixl0 -c 2
```
nothing happens, no counters going up to tell about any incoming frame.
```
# sysctl -d dev.ixl.10.debug.switch_vlans
dev.ixl.10.debug.switch_vlans: HW Switch VLAN Configuration
# sysctl dev.ixl.10.debug.switch_vlans=0x9200
# dmesg | tail -1
ixl0: Setting switch config to switch_tag=9200, first_tag=0000, second_tag=0000
# tcpdump -eni ixl0 -c 2
23:49:16.356591 dc:39:6f:0a:10:78 > a0:23:9f:37:29:3f, ethertype 802.1Q-QinQ (0x88a8), length 78: vlan 2, p 0, ethertype 802.1Q, vlan 140, p 0, ethertype IPv4, 91.137.26.17 > 2.207.28.131: ICMP host 91.137.26.17 unreachable - admin prohibited filter, length 36
23:49:17.129581 00:1d:aa:d8:3d:99 > 00:07:b4:00:78:01, ethertype 802.1Q-QinQ (0x88a8), length 93: vlan 2, p 0, ethertype 802.1Q, vlan 140, p 0, ethertype IPv4, 5.102.161.204.33305 > 224.0.0.251.5353: 27179 PTR (QM)? 192.168.10.3.in-addr.arpa. (43)
```