UniFi – Layer 3 methods for UAP adoption and management


Readers will learn the different layer-3 methods for deploying UAPs.

In many deployments where it’s not possible/desired to have controller running at the premise, you can run the controller in the cloud or your NOC. Say we have a large-scale project with many UAPs, we could:

  • On Amazon, create a virtual controller instance on EC2.
  • Configure/stage a few APs in our lab and customize the guest portals.
  • When we’re at the customer’s site, open a browser to the cloud-based controller.
  • Either configure DHCP server, DNS server, or simply use the UniFi Discovery Utility to make all local APs inform back to the controller.
  • On-going management/monitoring can be done anywhere and Amazon would provide us with great firewall configurations.


  1. Initial setup
  2. Discovery utility
  3. DNS
  4. DHCP option 43
  5. SSH


Initial setup

Please make sure you’re familiar with how UniFi works (e.g. where AP and Controller is in the same L2) before you attempting L3 Management. L3 management adds many moving parts in the mix (i.e. added complexity).

UniFi AP has a default inform URL http://unifi:8080/inform. Thus, the purpose of using DHCP option 43 or DNS is to allow the AP to know the IP of the controller.

Discovery utility

Not many environments can have a DHCP server that’s configurable, even less likely with a DNS server. That’s where UniFi Discovery Utility comes in. It listens to the multicast/broadcast packets from UniFi APs and allow you to tell the AP to inform any URL you’d like. (only APs in default state or not in contact with any controller will be displayed)

UniFi Discovery utility is installed along with your UniFi controller.

  • On Windows, it’s in Start Menu->Ubiquiti UniFi->UniFi-Discover
  • On Mac, /Applications/UniFi-Discover.app (or use Spotlight to find it)
  • Run “java -jar /lib/ace.jar discover”

To perform L3 adoption with the discovery utility:

  1. Wait until the AP shows up
  2. If the AP is not in default state. click “reset”, specify the SSH username/password and click “Apply”
  3. Click on “manage”, modify the inform URL and leave the SSH username/password as ubnt/ubnt and click “Apply”
  4. Open a browser to your remote UniFi controller and you should see it being “Pending Approval”
  5. Click on “adopt”. You’ll see it going to “Adopting” state, ignore it as it’ll eventually become “Adoption Failed” or “Disconnected”
  6. perform [step 3] again (no need to wait for [step 5] to finish)
  7. AP is now managed by the controller

Once adopted, the Controller will upgrade these units automatically.

The option of the Ubiquiti Discovery Tool Chrome Extension is also available, downloadable directly from Google Chrome here, or from our UBNT download page.

Note: If your L3 controller is available over the WAN then you need to make sure the necessary ports are open at the controller side (minimum port 8080 for inform). If you do not have a static IP then you may want to consider using a dynamic DNS service, and use the domain name instead of the IP for the inform address. If you’re using a USG then you can use the DDNS client that is available on that device itself. 


  • You’ll need to configure your DNS server to resolve ‘unifi’ to your controller’s IP address. Make sure that AP can resolve controller’s domain name. For example, if you are setting http://XYZ:8080/inform, then ping from AP to determine if XYZ is resolvable/reachable.
  • Or, using FQDN for the controller inform URL, http://FQDN:8080/inform
  • Troubleshooting – AP (with static IP) fails to connect to the L3 controller
    • when configured an AP from DHCP to static in the controller UI, make sure you have put the IP of DNS. If not, then the AP cannot contact DNS to resolve controller domain name.
    • if the AP has been reset (by pushing reset button), make sure that you have informed AP twice (using discovery utility) about the controller’s location (this will be improved in the coming release 2.3.0)

DHCP option 43

If using Ubiquiti’s EdgeMax routers, then DHCP option 43 can be done by just entering the IP address of the UniFi controller in the “unifi” field on the dhcp-server.

To use DHCP option 43 You’ll need to configure your DHCP Server. For example:

Linux’s ISC DHCP server: dhcpd.conf

# ... option space ubnt; option ubnt.unifi-address code 1 = ip-address;  class "ubnt" {         match if substring (option vendor-class-identifier, 0, 4) = "ubnt";         option vendor-class-identifier "ubnt";         vendor-option-space ubnt; }  subnet netmask {         range;         option ubnt.unifi-address;  ### UniFi Controller IP ###         option routers;         option broadcast-address;         option domain-name-servers,;         # ... } 

Cisco CLI

# assuming your UniFi is at ip dhcp pool  network   default-router  dns-server  option 43 hex 0104C0A8030A # -> CO A8 03 0A  # Why 0104C0A8030A ? # # 01: suboption # 04: length of the payload (must be 4) # C0A8030A: 

Mikrotik CLI

/ip dhcp-server option add code=43 name=unifi value=0x0104C0A8030A /ip dhcp-server network set 0 dhcp-option=unifi  # Why 0104C0A8030A ? # # 01: suboption # 04: length of the payload (must be 4) # C0A8030A: 

Cisco has a good write-up for DHCP option 43 setup.

To use IP of controller
  • You can also use the IP of the controller in the inform URL instead of the domain name.


If you can SSH into the AP, it’s possible to do L3-adoption via CLI command:

# 1. make sure the AP is running the same firmware as the controller. If it is not, see this guide: Upgrading UniFi firmware via SSH. # 2. make sure the AP is in factory default state #    if it's not, do #    syswrapper.sh restore-default # 3. ssh into the device and type mca-cli # the CLI interface: set-inform http://ip-of-controller:8080/inform
# 4. after issuing the set-inform, the UniFi device will show up for adoption. Once you click adopt the device will appear to go offline.
# 5. once the device goes offline, issue the set-inform command again. This will permanently save the inform address, and you'll see the device will start provisioning.

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