In wireless mode, after bridging the wireless (WLAN) interface to a LAN or DMZ zone, the WLAN zone becomes the secondary bridged interface, allowing wireless clients to share the same subnet and DHCP pool as their wired counterparts.
To configure a WLAN to LAN Layer 2 interface bridge
Click the Configure icon for the wireless interface you wish to bridge. The Edit Interface dialog displays.
If you have a virtual access point configured, then you already have a VLAN interface under an interface, such as X4, in the WLAN zone, and your virtual access point is configured to use that VLAN ID.
From Layer 2 Bridged Mode, select Mode / IP Assignment.
Although a general rule is automatically created to allow traffic between the WLAN zone and your chosen bridged interface, WLAN zone type security properties still apply. Any specific rules must be manually added.