6 step guide to troubleshooting your UniFi access point

Are you struggling to adopt your UniFi access points onto your UniFi controller?  Here are a few useful troubleshooting methods to resolve the issue. 

Before you can adopt access points (AP) and push configurations like WLAN, client limitations and channels from your Ubiquiti AP’s to service connecting clients, your UniFi controller software has to be up and running. Although, in some cases, access points struggle to adopt onto the UniFi controller, which is why we have created this guide to help you diagnose and address this issue. 

      1.Ensure that your access point firmware is up to date.

If your access point is showing in your UniFi controller, it might require a firmware upgrade prior to being adopted.  Simply click on the upgrade option and the controller will take care of the rest.  The only requirement here is a stable Internet connection and not to power cycle the access point during the update.  

Use the manual set-inform command via SSH:

      2. If your device does not appear in the UniFi controller then use the following steps:

i. Connect to the device via SSH

ii. Run the command “sudo syswrapper.sh restore-default” and wait until your device reboots. iii. SSH into your device again and run the following command (sub “IP-of-controller”) with the IP address of your UniFi network controller host: set-inform http://IP-of-controller:8080/inform

b. After executing this command, your UniFi device will show up in the Devices section on the controller and you can click on the adopt option. 

       3. Check VLAN configuration of the switch:

a. If all devices that are connected to the switch are unable to be adopted, ensure that the VLAN configuration on the switch isn’t preventing devices from connecting to the UniFi Network controller. 

       4. Ports blocked by firewall 

a. The following symptoms indicate the traffic can go from the device to the controller, but not vice versa:

i. The devices can be discovered 

ii. You can ping and SSH into devices 

iii. You can initiate the adoption process, but get the adoption failed error 

b. To fix this issue:

i. Ensure that port 8080 is open inbound on the device hosting the UniFi network controller 

ii. Configure any firewall device between the controller and the device to allow traffic. 

       5. DHCP server issues during AP adoptions 

a. If the UniFi access point continues with the default IP of 192.168.1.20, this indicates an issue with the DHCP server

i. To fix the issue:

     1. Ensure that the AP  can communicate with the router 

     2. Ensure that the router leases a DHCP address to the AP 

     3. Ping the AP 

     4. After a successful ping, SSH into the AP and get the output of the command (this will provide details on the AP Firmware, model and the status of the AP) 

      5. Ping the controller host / PC IP address and then enter the command set-inform to point the AP to the controller system. 

b. If the AP is not listed on the DHCP lease on the router, this indicates that there is no communication between the AP and router.  In this case, follow the below steps: 

i. Switch the cables 

ii. Reboot the affected AP 

iii. If another laptop/pc or AP is available, connect it to the same port to check if it gets a valid IP address and shows up on the routers DHCP leases table. 

c. If the other device (laptop or AP) is getting a valid IP address, this indicates a firmware or hardware problem with the AP.  To fix this, SSH into the AP and reset it by using the command syswrapper.sh restore-default

d. If other devices are also not getting a valid IP address, this will be related to the DHCP request reaching the routers.  In this case, you can perform a packet capture to check if the DHCP request on port 67 or 68 is reaching the DHCP server/routers. 

      6. Double NAT

a. If you have two NAT devices like a modem/router combo and a USG,  there might be a possible network overlap between the two devices.  This can result in no Internet connectivity for the devices that are behind the USG on your network topology. 

b. To fix this issue, switch your modem/router to bridge mode.

Join our upcoming Ubiquiti Enterprise Wireless Admin course that will be taking place at our Centurion branch from 10 – 11 December 2020. During this course, we will take a look at some of the most important concepts in Enterprise Wireless Networking, with special emphasis on best practices for designing and managing your UniFi WLANs.  Learn with hands-on lab activities using the latest generation of UniFi APs, as well as the UniFi Controller platform.

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