UniFi Adoption with Devices on Separate Subnet from UniFi Controller

This is, as always, is maybe more of an aide-mémoire for me, but may be helpful if someone else is searching for a solution…

Here is the scenario: My UniFi devices are on a separate subnet from my UniFi Controller. The problem, if you will, with this configuration is that when a UniFi device looks for the UniFi Controller is that is cannot find the Controller on a different subnet.

There are a number of ways that this can be resolved (other than putting the Controller on the same subnet) as documented in UniFi – Device Adoption Methods for Remote UniFi Controllers. The option that I took, or maybe it is two options, is:

  1. I configured my DNS server with an alias that allows unifi to resolve to the UniFi Controller. That way when a device restarts (such as after a reboot, power loss) it can find the controller when it boots and executes the set-inform http://unifi:8080/inform. The hostname unifi will resolve to my UniFi Controller.
  2. In my DHCP configuration (on pfSense), I added DHCP Option 43. You have to add 01:04 to the hex version of the IP address of your UniFi Controller. Browserling has a page to convert the IP address to hex: Convert IP Address to Hex Format.

One important thing to remember: If you statically set the IP addresses of your UniFi devices you will not get the DHCP Option 43 provided to the devices.

About Mike Pelley

Let’s see… A little about me… I’ve been around information technology since 1983 with computers such as DEC Rainbows (weird machine – the standard DOS couldn’t format its own floppy disks – remember them? – and I had to format them on a friend’s IBM PC) to Radio Shack TRS-80 to Apple ][e and Apple //c in the beginning. I have programmed in 8-bit assembly language on 6502, FORTRAN and COBOL on IBM System/370 (and I still hate JCL), VAX BASIC and COBOL (and a weird and massive WordPerfect 4.0 macro) on DEC VMS (Alpha), C/C++ on Digital Unix (ALPHA), and C/C++, Perl (it may be powerful but I still hate it), PHP on Linux (Red Hat, Centos, Ubuntu, etc.). I have work with databases such as Digital RDB (later to become Oracle RDB), Oracle DBMS, Microsoft SQL Server, MySQL and PostgreSQL on VAX, Alpha, Sun and Intel. Check out my professional profile and connect with me on LinkedIn. See http://lnkd.in/nhTRZe I still think that Digital created some of the best ideas in the world: VAX clustering, DSSI disks (forerunner to SCSI) and the Alpha processor (first commercial 64-bit processor – Red Hat screamed on an Alpha!). DEC just could not seem to be able to give air conditioners away to someone lost in the Sahara Desert! VMware is one of the best ways to get the most out of an x64 server. And I have tried Oracle VM, Virtual Box and Microsoft Virtual Server. Outside of that I am a huge military history buff starting in the early 20th century. I love Ford Mustangs (my ’87 Mustang GT was awesome) and if I had the money I would have a Porsche 928S4. If I had a lot of money I would have a Porsche 911 Turbo. I also play too much AmrA 3 Exile mod. Over 5,000+ hours... I have a wonderful son, Cameron. I have a long suffering (Do you really need all that computer junk?) wife, Paula. I live in Paradise, Newfoundland and Labrador.
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One Response to UniFi Adoption with Devices on Separate Subnet from UniFi Controller

  1. Grant says:

    Hi Mike, I’m currently struggling through PFsense, ProxMox, Pop-OS and Unifi. I just came across your post and blog as I was searching for answers to the finding the Unifi Switch on a different VLAN. However, when I got to the bottom of the post and read a bit about your history, it made my day. I started with DEC PDP-8s in 1978 programming Dibol and joined DEC in 1980 with Field Service and stayed for almost 15 years, changing between hardware and software departments every few years. Loved DECnet, Clusters, Rainbows, and Alphas. I ended up being the Digital Rdb guy in our office and have fond memories of much of what you mentioned.

    Thanks for the stroll down memory lane and I may hit you up with PFSense and Unifi questions. Thanks. Grant

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