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Community Member

AP continuously renewing IP address


Hi Friends,


 I installed 4 new access points in our remote site to register it to the controller in the HQ using flex connect. And configured the distribution switch in the remote site as  dhcp server. 

 A new vlan was created for this purpose.


 Now, the APs are getting the IPs, but they are continuously renewing it, say every 20 - 30 seconds.


 The interfaces connected to the APs are stable. No ups and downs..


 What could be the reason.?


 Configs below;

Ip dhcp pool AP_MGMT



 option 43 ip


interface fa5/35

  description to AP

  switchport mode trunk

  switchport trunk native vlan 777

  no shutdown






Hi,The reason the APs are


The reason the APs are continuously renewing their ip is because they cannot find a controller to register.

Please change the option 43 and use in HEX format.

option 43 hex f1040a01023c.



Community Member

  OK.  I will try it and get




 I will try it and get back.

 So, to summarize, if the Controller is not reachable the AP will renew its IP...that's its behavior.

 Thanks for that info.

Community Member

 The controller was not


The controller was not reachable from the AP's IP address. The Firewall rule was changed and now its working fine.


Hi,You need to make sure


You need to make sure below points and then check.

You can deploy a FlexConnect access point with either a static IP address or a DHCP address. In the case of DHCP, a DHCP

server must be available locally and must be able to provide the IP address for the access point at bootup.

FlexConnect supports up to four fragmented packets or a minimum 500-byte maximum transmission unit (MTU) WAN link.

FlexConnect is supported only on the following access points: Cisco Aironet 1130AG, 1140, 1240, 1250, 1260, AP801, AP802 and Cisco Aironet 600 Series OfficeExtend Access Points.

Round-trip latency must not exceed 300 milliseconds (ms) between the access point and the controller, and CAPWAP control packets must be prioritized over all other traffic. In cases where you cannot achieve the 300 milliseconds round-trip latency, you can configure the access point to perform local authentication.

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