Cisco 140ac Access Points Static IP Changes to DHCP Address

[ronb7gens]

Good Day,

I have just installed 18 new Cisco 140ac access points in one of my school networks.  WIFI is working fine, devices are connecting and no issues there.  Using the Management Web GUI, I can see all 18 APs, but sometimes they won't have the static IP I have assigned to each of them, rather they take an address from the DHCP pool.  Not happening on all of them, just random ones (management AP is rock solid with its addresses).  For the DHCP addressed units, I change the address type to Static IP, set the preferred IP address, ensure the subnet and gateway is correct, and then Apply the changes.  Then I save the configuration using the Disk icon at the top of the web gui pages.  All should be good, but as I continue to monitor, an AP might drop off the list, then reappear, with a DHCP address sometimes.  

I am using POE switches and the units are spread over seven switches, so there shouldn't be a power issue.

Am I missing anything with regards to the configuration of these units?  Anyone else having similar issues?

Thanks.

[marce1000 · Accepted solution]

 - In general you are fighting against the wrong problem , have the ap-addresses being provided by DHCP all the time , 

 M.

[ronb7gens]

In the past, with earlier APs, I always did static ips and thought that was the preferred / recommended method, so I continued with these units.  So the only static ip should be the management address, the rest can just go DHCP and life goes on?

Thanks for your quick reply and insight.

[Scott Fella]

I think everyone in the past have also done static.  I was one of them for the longest time, but in the last 10 years, I have been using dhcp and the reason was because Cisco ap's if they were not able to find a controller, would reboot and request a dhcp address.  When this was implemented way back when, that is when static address wasn't worth it because the ip address would change.  A good example is if there was a network issue and the controller was down or not reachable.  The ap's would continue requesting new ip addresses and when using a MS dhcp, would cause bad ip address on the dhcp pool.

You can always do mac address reservations if you wanted the ap to always get the same ip address.

[ronb7gens]

Scott,

Thanks for the details about using DHCP.  My method has always been static, but it is good to know that DHCP works just as well.  I wouldn't bother with mac address reservations if the APs don't have to be set with a particular address all the time.  I also used static ips outside of my address pool so I wasn't taking pool addresses away from the school network DHCP pool.  I can get around that by increasing my pool size accordingly.

[ronb7gens]

I am going to leave the static ip addresses as is for now, they all appear to be stable over the last 1.5 hours.  I will plan on a future school visit to release my APs from their static prison and let them run free.

Thanks to marce1000 and Scott Fella for your quick and knowledgeable replies and information. This is good information for now and for going forward (I have two other schools with similar setups, all static, and I am looking at one more school to re-fit with the 140ac units).  I will probably change the other two schools to DHCP on future visits as well.

This Cisco community is fantastic - the amount of knowledge and quick responses is extremely helpful.