Cisco CCNA (200-301)Network AccessMedium
A technician is configuring a new Cisco Access Point (AP) to be managed by a Wireless LAN Controller (WLC). The AP has been physically connected to the network and powered on. The technician observes that the AP is not joining the WLC. Upon checking the AP's console, the technician sees messages indicating that the AP is 'Discovering WLCs'. Which of the following methods is NOT a valid way for a Cisco lightweight AP to discover a WLC?
- ADHCP option 43
- BDNS resolution of 'cisco-capwap-controller.localdomain'
- CBroadcasts on the local subnet
- DManually configured WLC IP address via AP console
Show answer & explanationAnswer & explanation
Correct answer: B. DNS resolution of 'cisco-capwap-controller.localdomain'
Cisco lightweight APs use DNS resolution of 'cisco-capwap-controller.localdomain' (or 'cisco-lwapp-controller.localdomain' for older LWAPP APs) to discover WLCs, not 'cisco-capwap-controller.localdomain'. The 'localdomain' part is incorrect for the actual DNS entry used.
Why the other options are wrong
- A. DHCP option 43 is a valid and commonly used method to provide WLC IP addresses to APs.
- C. AP broadcast for WLCs is a valid discovery method on the local subnet.
- D. Manually configuring the WLC IP address via the AP console is a valid method, often used for initial setup or troubleshooting.
Cisco AP WLC Discovery Methods
Cisco lightweight Access Points use several methods to discover and join a Wireless LAN Controller (WLC) to establish a CAPWAP tunnel.
- Methods include DHCP Option 43, DNS, local subnet broadcasts, and manual configuration.
- DNS entry typically 'cisco-capwap-controller.local'.
- Order of preference can vary slightly but manual is often highest.
Memory trick: D.D.D. M. - DHCP, DNS, Discover, Manual