When I wake my Mac mini from sleep, it occasionally comes up with a dialog saying "The name of your computer "whatever" is already in use on this network. The name has been changed to "whatever (1)"" (or (2), I'm up to (4) at the moment).
The Mac is plugged in to the network via an ethernet cable and gets a DHCP assigned IP address from my router which runs pfSense. I have DHCP set to give the same IP address to the Mac's Mac.
Why does this happen, and more usefully, how can I make the machine stop renaming itself?
In System Preferences - Sharing I have 'File sharing' and 'Remote Login' enabled.