Hello Alexander, thank you for your report. Unfortunately I'll have to disappoint: I've no plans on extending arpwatch to be able to "follow" ethernet addresses. I also don't want to merge #527251, as it adds quite a bit of code that we would need to support. Substantial changes like that are typically done in the upstream project before they can make their way into Debian. However, in the arpwatch case, upstream has been inactive for a long time so I consider it very unlikely this will happen…
Arpwatch has always only "followed" IPv4 addresses (and never ethernet addresses), meaning if it sees an ARP message containing an IPv4/ethernet "binding" it will lookup previous ethernet address(es) using that IPv4 address. As you can probably imagine, changing the code to "follow" ethernet addresses too would be a substantial change. I wasn't aware the documentation is wrong in that regard. Thanks for pointing that out. I will probably change the wording to something similar to: new station: "There are no previous known ethernet addresses for this IPv4 address" So much for the bad news, I also have something that might help you: Since Debian version 2.1a15-4 (unfortunately not in stretch) arpwatch supports filters to ignore certain packets. So if you are happy with completely ignoring your Laptop's ethernet address in arpwatch (and after upgrading to that version), you could add add a filter to do that. Sorry I'm not able to offer more help. Have a nice weekend Lukas