1.
If you configure an access point to use a static IP address that is not on the same subnet on which the access point’s previous DHCP address was, the access point falls back to a DHCP address after the access point reboots. If the access point falls back to a DHCP address, enter the show ap config general Cisco_AP CLI command to show that the access point is using a fallback IP address. However, the GUI shows both the static IP address and the DHCP address, but it does not identify the DHCP address as a fallback address.https://www.cisco.com/c/en/us/td/docs/wireless/controller/8-0/configuration-guide/b_cg80/b_cg80_chapter_0100000.html
2.
(1)capwap ap controller ip address 10.10.10.10 - For IOS based AP
(2)capwap ap primary-base WLC-9800 10.10.10.10 - For ClickOS based AP, This also works in IOS AP even on the new Catalyst AP's.
FYI:-
IOS Access Points (1700/2700/3700 series)
COS Access Points (Cat9000,1800/2800/3800 series & 1562)
https://www.cisco.com/c/en/us/support/docs/wireless/aironet-1200-series/99763-reset-lwappconfig-lap.html
https://community.cisco.com/t5/wireless-mobility-documents/understanding-access-point-os-images/ta-p/3123952
3.
Controller>>Interfaces
If dynamic AP management is enabled AP's can register to the WLC over that port. ports you will see in a WLC are below
service port - Out of band Management Access
management - In Band management interface and dynamic AP management interface.
redundancy management & redundancy port - HA SSO related ports.
virtual - helps the redirect pages and dhcp process for local mode clients
Any other port configured may be for Local mode clients, these interfaces also can have dynamic ap management enabled. If it is Flex, then you really don't need interface in WLC as traffic dropped directly in to the switch where AP connected. (Due config mode you need to define an interface under WLAN, so you can create a dummy interface)
