Heads Up :
The post you are writing will appear in a public forum. Please ensure all content is appropriate for public consumption. Review the employee guidelines for the community here.
It's all based around the VLAN, the WLC's DHCP Scope will only hand out DHCP addresses for devices connecting to the SSID, the SSID should be tied to a VLAN with an IP address, the DHCP scope will be in the subnet of the VLAN.
You are correct, the PIX will not respond to DHCP Relay requests from the WLC. I've ran into this before and ended up configuring the Public wireless DHCP scope on the WLC, it works great.
