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VLAN implementation over WLAN

I have a wired network w VLAN of networks,, and so on. Is it possible to implement?

I have configured according to the cisco example document, but never able to get IP address even though i have set it to no open authenication.

Appreciate any advise/guidance.


Where is your DHCP server?

Are you using multiple SSIDs, one for each VLAN?

Do you have a Layer 3 device to connect / route between the VLANs?

Even if your DHCP server is on the AP, DHCP service are only available on the native VLAN. To get the DHCP requests/replys to other VLANs, you need a layer three device (router or L3 switch) to move the traffic from the native VLAN to the other VLANs.

Good luck


>>Where is your DHCP server?

my dhcp is using Windows 2000 server

>>Are you using multiple SSIDs, one for each VLAN?

yap. i have set the an native VLLAN & other VLAN as according the switch's VLAN.

>>Do you have a Layer 3 device to connect / route between the VLANs?

the AP1100 is connect to 3750 POE switch

My switch has been condigure for trunk mode, as per cisco example documentation.Just dont know where i have missed out.

I am sure that the hardware have no problems, as i earlier have access via the AP, the switch interface "switchport access vlan 200", local authentication by RADIUS.

Which VLAN is your DHCP server connected to? Is it on the native VLAN?

Do you have IP-HELPER configured on the AP-side of the switches virtual interface? DHCP starts the transaction with a broadcast from the client, routed interfaces block broadcasts by default, so you'd use IP-HELPER (only on the client-side of the interface) to forward those requests to your DHCP server.

The RADIUS requests work because they are unicast, and can be normally routed.

And, while you do not explicitely say so, I'm assuming that you have L3 mode enabled on your 3750, and each VLAN presents a routed interface.

Otherwise, just having the various VLANs hosted through a device doesn't mean they'll talk to each other. They are logically separate broadcast domains and require something acting as a router to move traffic from one VLAN to the other.

Good Luck


I have re-configured from scratch again, and i encountered DHCP problem. My test results shows that when i am using static IP, everything works well (including from different VLANs w different SSID). When i set "Auto DHCP",

via > AP > 3750 - fail,

I believe its the IP-HELPER you mentioned earlier.

Appreciate you guide me through.



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