Nonsense DNS lookups for own hostname

Hello! Recently I discovered something weird on my system: Seemingly every minute, it does DNS lookups for its own host names, which of course fail because I'm not in my ISP's DNS (and don't even have a dynamic IP, plus I'm on a local network with a firewall). Here is an extract from tcpdump: <<<

Nonsense DNS lookups for own hostname

Hello! Recently I discovered something weird on my system: Seemingly every minute, it does DNS lookups for its own host names, which of course fail because I'm not in my ISP's DNS (and don't even have a dynamic IP, plus I'm on a local network with a firewall). Here is an extract from tcpdump: <<<