Unifi Console DHCP Reservation Removal via SSH Failure

Ok so the title pretty much nails what I’m going to blog about here. I just recently setup a new Unifi system and I had started making reservations for various devices including making a reservation that was attached to the wrong MAC address (my mistake there). In having it attached to the wrong MAC and that I’m using a Unifi Dream Router, I couldn’t access the old interface to rip out the offending entry and I was having a hell of a time finding the result via a Google search. That said, this post led me to somewhat understanding the current structure of the underlying Linux OS.

I did the following:

vim /ssd1/.data/udapi-config/ubios-udapi-server/ubios-udapi-server.state

Once the file was open, I searched for staticLeases and in that section I kept going until found the following:

     {
      "addresses": [
       "172.25.25.11"
      ],
      "id": "00:00:00:00:00:00"
     },

I cleared out the whole section there. I then went to this file and it’s sibling (same name with .prev appended to the end)

vim /ssd1/.data/udapi-config/udapi-net-cfg.json
vim /ssd1/.data/udapi-config/udapi-net-cfg.json.prev

I cleared out the following code from there as well:

     {
      "id": "00:00:00:00:00:00",
      "addresses": [
       "172.25.25.11"
      ]
     },

I then rebooted the UDR and checked the following file to see if an entry had been added.

cat /run/dnsmasq.conf.d/dhcp.dhcpServers-net_Default_br0_172-25-25-0-24.conf

dhcp-host=set:net_Default_br0_172-25-25-0-24,00:00:00:00:00:00,172.25.25.11

The above line was no longer present, but despite all of my attempts at removing any entries I could find, there is still something in there holding onto the IP address. From what I have read, this is a common issue that when using a higher grade device, is easy to resolve via the legacy interface. I don’t have access to that, so I’m basically up a creek until I can figure out where it’s hiding in the system. The device in question is currently set to static in it’s main OS, but I would like to have the reservation anyways since that is how I normally do it. Also, it shouldn’t be this hard to view an existing config without needing the devices to have actually come onto the network. This is bananas.

Addendum: I was discussing this with some friends and a suggestion was to try the following: (It didn’t work since the IP was stuck deep in the config somewhere…)
Take the original machine and assign it a different IP statically than what you really want. That should force it to change the assignment. Then, take another machine and assign it the original IP you would like to use. After you do that and both computers pick up the new IP’s, you delete the computer from the system so it forces the entry to be fully deleted. This process can take hours for the whole system to sync up, so do it over a weekend or something. Then once the entry is deleted, you can then delete the original computer’s entry as well and give it the correct IP address you want it to have.