After some more digging I found this behavior roots from the DNS Resolver running on the Router (a Turris Omnia)
Local hosts get a name xxx.home.example.com from fixed DHCP leases and the knot resolver (kresd) on the Turris responds with the local IPv4 Address for this hosts. Queries for IPv6 Addresses of xxx.home.example.com get a NXDOMAIN response from kresd. systemd-resolved queries for A and AAAA records, the A request gets used and the subsequent AAAA NXDOMAIN responce leads to a cache flush and a negative caching for the name. After tracking down the behavior a workaround in the turris kresd configuration was proposed (https://github.com/CZ-NIC/turris-os- packages/commit/42da887f8165dccc374c73c3ed9e024fba7b0c3e). This fixed my problem. Thanks, this bug can be closed, the source is not in systemd -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1795913 Title: Systemd Resolver works unreliable to local DNS Names To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/systemd/+bug/1795913/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
