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DHCP Pool binding to a SSID?

Hello all!

I have an AP with multiple SSID/VLANs. The management of the AP is via VLAN 1. I also have VLANs X and Y binded to SSIDs VLANX and VLANY respectively.

I have created a DHCP pool that I want to bind to only SSID VLANY users (not VLANX users). My question is, how do I apply this DHCP pool to SSID VLANY - otherwise the AP doesn't know which SSID to apply DHCP to!!

Hope this makes sense, and hopefully someone has the answer!



Re: DHCP Pool binding to a SSID?

DHCP automatically looks at the DHCP request which contains a relay IP. The Relay IP determines which scope to hand IPs out from.

For instance, say vlan x is and vlan y is Your controller has IP in vlan x, and in y. When a user connects to an SSID mapped to vlan y, the controller sends a request to the DHCP server (or itself if it is the DHCP server for the segment) with a relay IP of The DHCP server sees it has a scope for network 10.1.1.x with available IPs of 3-254, so it hands out the next available in that range.

I hope this helps,


Community Member

Re: DHCP Pool binding to a SSID?

I appreciate your response Eric :-)

However, I know how DHCP works, but my problem is this:

I have VLAN2 assigned to SSID Test. On VLAN2 is a DHCP server which hands out IP addresses no problem. I also have VLAN3 assigned to SSID New-Users. I want the Access Point to give these users IP addresses via DHCP. The Access Point has an IP address in its own VLAN4. Now my problem is: Once I have defined a DHCP pool on my access point, how does the access point know which VLAN/SSID to apply the DHCP pool to? How does it know to apply it to DHCP requests in VLAN3 only - and not VLAN2 or any other VLANs/SSIDs I have configured and that use DHCP.

I hope it is clear what I am trying to do.

Many thanks


Re: DHCP Pool binding to a SSID?

Apparently I was still waking up, and made several flawed assumptions in my response. I thought this was a controller environment.

So I believe the only way to have an Autonomous AP serve DHCP for a segment other than the one it has an IP on is to set up a helper address on the router on that VLAN pointing to the AP IP. In this case, on the default gateway for VLAN 3 I would add an IP helper address pointing to the AP IP in vlan 4.

This config is pretty much the same as a standard switch. While it allows client access to multiple VLANs, it only participates in layer 3 activity in its management VLAN.

Please let me know if this makes sense and if I'm understanding your setup.

Community Member

Re: DHCP Pool binding to a SSID?

You understand my set-up perfectly now :-)

I was hoping that the AP would be able to serve IP addresses without any ip helper addresses configured elsewhere. In other words, the AP hears DHCP discovers and responds accordingly. As I initially thought, it seems this cannot be done. The way to go the is how you described - configure a helper address pointing back to the AP management IP address.

Thanks for the response, I will rate you accordingly!

Community Member

Re: DHCP Pool binding to a SSID?

Hi Darrenj:

The reason it didnt work the config is because in the config the radio interface is in a bridge group with the ethernet interface. Since DHCP requests are broadcast, and the radio is in a bridge group, the dhcp request gets sent straight out the ethernet interface. In order to make it work, if your access points ethernet interface is attached to, for example, a cisco router, like mine is, i went onto the routers ethernet interface and configured a ip helper-address which points back to the BVI interface of the AP. DHCP will then work fine.

best regards


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