I have a Linux based wireless access point. It has eth0 interface for ethernet, ath0 for wireless and br-wan as a bridge between the two.

bridge name     bridge id               STP enabled     interfaces
br-wan          8000.001567000041       no              eth0

Q: How can I add vlan tagging on the wireless side so that all the outgoing traffic will be tagged, and only incoming tagged traffic will be accepted?

I'v tried creating a new vlan using vconfig

vconfig add ath0 15
ip link set ath0.15 up

I then used a computer with a traffic generator software to send frames through the Ethernet port of the access point. Using tcpdump -e I can see them pass through both ath0 and ath0.15, however no tagging is added whatsoever.


I think you need to add the ath0.15 device to the bridge:

$ vconfig add ath0 15
$ ip link set ath0.15 up
$ brctl addif br-wan ath0.15
$ brctl delif br-wan ath0


  • I'v tried it, yet it seems that no tagging is beeing done on ath0.15. When checking with tcpdump both ath0 and ath0.15 transmit the same frame. – DoctorBurp Sep 8 '13 at 8:08
  • 1
    @DoctorBurp - have you tried just getting the vlan tagging to work on ath0 first, prior to getting it to work on the br-wan? Just a thought – slm Sep 8 '13 at 11:56
  • @sim - Your thought is right, regardless of working with the bridge, no tagging is done. I will need to check the drivers in depth. Thanks. – DoctorBurp Sep 9 '13 at 5:25
  • @DoctorBurp - hey did you remember to load the kernel module 8021q? modprobe 8021q will do it. – slm Sep 9 '13 at 5:34
  • I do not have it loaded, but I dont think I need to. My access point is openWRT based. When compiling the kernel using ltib I'm selecting 8021q support to be built-in instead of external module. – DoctorBurp Sep 9 '13 at 14:18

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