macOS renaming itself...

[pchrichard]

We use a script to rename our Macs along the lines of DA-%SERIALNUMBER%

For the last year or so, around half of our estate (I expect those using our campus network) regularly renames itself along the line of DA-FVFHF4BGQ05F (6), the suffix number incrementally increases and we have some devices with hostnames that end (533) or greater. This obviously looks a total mess.

I don't fully understand why this happens, nor how to prevent it - I presume it relates to the device wanting to avoid a duplicate name on the network, which in our case would only be itself, so it's confusing why it happens at all.  WIndows isn't affected in the same way. I suspect the ultimate fix would be something at network level, but wonder if anyone knew the root cause, or had dealt with this via macOS config and/or Jamf?

[patrickj]

Do any of these devices happen to use multiple connection types? For example Wi-Fi and an Ethernet adapter on the same network? I've seen instances where it can cause a hostname conflict.

[pchrichard]

Hi Patrick, thanks for this.  Upon investigation, it does appear that all Macs affected are using both ethernet and wifi... is there anything configurable in MacOS to ignore this hostname conflict?

[jtrant]

I don't think there's a way around this behavior, but I set up an EA to check if the hostname was valid, and if not, rename the Mac once a week.

Happy to provide both but we name our systems to S/N so it might not be too useful.

[Gratti]

Hey Jrant, would you be able to provide me with that script as well? We're seeing the same issue in our environment.

[pchrichard]

Thanks, jtrant - sounds useful, could you send over your script?