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WAP321 multi ssid with different VLANs DHCP issue

Hi All,

Setup a WAP321 with the new firmware. Setup 2 SSIDS:

WIRELESS (vlan:1)

GUEST (vlan:99)

The wap is plugged directly into a port on my router so I configured the port and additional vlan99 port. I have a DHCP scope assigned on the router to both the port and port.99 interfaces.

clients on WIRELESS have no problem and work correctly, however when a client joins guest...a packet capture on the router port shows that a dhcp request is being received for the same MAC on both untagged and tagged 99 interfaces....thus it appears the WAP is not handling the vlans properly

16:07:10.566932 PortA, IN: IP > BOOTP/DHCP, Request from 84:c9:b2:78:fc:31, length 331

16:07:10.566947 PortA.99, IN: IP > BOOTP/DHCP, Request from 84:c9:b2:78:fc:31, length 331

This is pretty generic setup im trying to achieve here...surely im just doing something wrong??



Everyone's tags (5)
Rising star

Re: WAP321 multi ssid with different VLANs DHCP issue

Hi Court,

thought i would try to simulate the issue you are having , so put together a UC520 , SG3000-10P and the WAP321.  All these devices are VLAN aware.

I have the same firmware as you on the wap321. 

I had no issue adding VLAN 100 to WAP321, seems simple enough, with no traps for the unwary..

But since you mentioned a VLAN issue, I used the WAP321 internal packet capture utility to  see what was going on, specifically with vlan 100 . What follows is;

  1. the wireshark capture ,
  2. WAP configuration.
  3. switch port  to VLAN configuration for VID=100  

I could see from the wireshark capture that the correct scope is getting to my wireless IP phone connected onto VLAN 100 via SSID=uc520-voice.

You will note the wireshark capture also displays the VLAN ID.  So i gotta think at this stage that there is something wrong with your network VLAN configuration.

I have my WAP connected to switch port 8 on my SG300-10P.  You will note that I have tagged switch port 8 as a member of VLAN 100.

I suggest to try the wonderful folks at SBSC to see/validate  if the WAP configuration is configured correctly .  But you have my example above.

When I added the extra Virtual AP1 called uc520-voice and assigned VLAN ID=100 to it, the AP automatically made the copper port of the WAP321 tagged in VLAN 100.

regards Dave


Re: WAP321 multi ssid with different VLANs DHCP issue

Hi David,

Thanks for your detailed response, its greatly appreciated.



Hi,I know this is a very old


I know this is a very old post but I was having the exact same issue on my WAP321 access points and i just found the solution, and whilst David's response below was comprehensive it didnt give a fix to the problem.

So i have management VLAN 12, VAP0 also on VLAN12 (and working fine), new VAP1 on VLAN17 wasnt getting any DHCP.

The fix (at least for me) was to go to LAN -> VLAN and IPv4 -> untick 'ENABLE' Untagged VLAN - i.e. ensure untagged traffic is disabled.

After doing this i lost management of the WAP so I changed the switch port its connected to, into a TRUNK port rather than access port and management was restored.

I then tested wifi on the two vlan's and that was now working.

Hope that helps someone.