Generally, UniFi APs will be installed in a configuration where there is a central server (What we would call a “controller”) that manages all of the UniFi APs on the network. This allows us to perform a single change that will be propagated to all of the APs automatically. This controller is either software based (free), or hardware based (UniFi Cloud Key / UniFi Security Gateway / UniFi Dream Machine).

However sometimes you may only have one AP in your network and you do not need all of the fancy features that the controller provides. Or perhaps you want to use the AP in a network environment where you are unable to use a controller. Luckily, UniFi APs do not strictly require a controller in order to operate. In these cases, the AP can function in Standalone Mode - however it has some quirks

The AP functions without needing DHCP

This is sort of obvious, given that access points belong to Layer 2 of the OSI stack - but I thought it would be good to reiterate it here.

The access point doesn’t need to be assigned an IP address from a DHCP server on the network, as it is just a network bridge. Devices that connect to the AP therefore also do not need an IP address leased by a DHCP server; they can statically assign their own.

UniFi Controller is limited when configuring standalone devices

The only settings you can change from the UniFi Controller app on your phone are basic WiFi, radio settings (SSID, Password, Channel, TX/RX Strength) and smaller insignificant options. You miss out on band steering, airtime fairness, and uplink connectivity monitor functionality.

The lack of the latter setting is quite undesirable, as you have to change it over SSH since the option is not available in-app. Any changes that are made over SSH will be reset if you perform a Save from the UniFi controller app.

The AP will enter Isolated Mode if it does not detect a working uplink/gateway

UniFi’s Uplink Connectivity Monitor feature detects if the device is able to reach the internet (or a defined address) through its available network interfaces. If it is unable to, the device will enter Isolated Mode - where its radios will stop broadcasting, and it will attempt to mesh to a linked access point.

However, in the scenario that your network does not have internet connectivity (i.e. a network purely for ad-hoc communication) - this will stop you from using your UniFi AP. In order to get this to work, you will have to disable the Uplink Connectivity Monitor - however you cannot disable it in the UniFi Controller app without first adopting it.

The solution to this is to SSH into the device, and modify the /tmp/system.cfg file.

• Connect the AP to a wired network (or do the below steps REALLY fast)
• Edit the file
  • vi /tmp/system.cfg
  • Change connectivity.status=enabled to connectivity.status=disabled
  • Save and close the file
• Type save to write the changes to the device
• Type reboot to restart the device

Note: This change will be reverted if you apply a Save from the UniFi Controller app

Changes to the *.cfg files will not save when you Save from the UniFi Controller app

I’ve mentioned this twice already, but for the sake of importance…

Changes made to the cfg files (that you performed via SSH) will not be kept if you press the Save button in the UniFi Controller app.

So make sure to re-apply any changes that you may have made

Note: tbh there’s probably another cfg file which you change (perhaps the /tmp/default.cfg file???) that will keep the changes even when you press Save