My /etc/resolv.conf (and also /run/systemd/resolve/resolv.conf) contain a search entry for wifi.ns.nl that I did not put there and do not want there. It seems related to a problem I have now in that I cannot resolve some web addresses. The resolv.conf files are managed by systemd-resolved and tell me not to edit them manually. If I do that anyway nothing changes and if I restart sytsemd-resolvd it changes the resolv.conf files back to their original state.
The search wifi.ns.nl line probably appeared after I tried to connect to a captive wifi network run by ns.nl. After connecting to the wifi, but before accepting the terms on the web portal, I tried to connect with SSH to a server. That didn't work, and accessing any other website through the wifi also did not work. When I came home and connected to my home network, connecting to the server I wanted to connect to still didn't work, and systemd-resolve now says resolve call failed: No appropriate name servers or networks for name found for that server and for *.wifi.ns.nl. (I can still connect to the server using the ip address, and I can resolve the name using dig on a remote dns server, so the problem is only my local DNS resolver.)
If I do systemd-resolve --status it also tells me 'wifi.ns.nl' is one of my global DNS Domains.
Apparently something somewhere has remembered some setting probably related to the captive wifi network and wifi.ns.nl. I've tried restarting systemd-resolved, networking, network-manager, but the search entry is still there.
(I also did a sudo grep -R wifi.ns.nl /etc, it doesn't find 'wifi.ns.nl' anywhere else under /etc other than the resolv.conf file)
How can I remove that search entry, other than rebooting my system?
It seems to be the bug described here. If both systemd-resolved and the
resolvconfpackage are installed they fight over who gets to manage/etc/resolv.conf. If there are anysearchlines in that file these domains break for a reason I don't quite understand yet.In my case, with both installed
/etc/resolv.confwas a symlink to/run/resolvconf/resolv.conf. After removing theresolvconfpackage it became a symlink to/run/systemd/resolve/stub-resolv.confand after restarting thesystemd-resolvedservice that fixed the problem.I have the same problem, and the simplest solution is to edit
/etc/resolve.confand remove the 'search' lines.No restarting required, and things work again.
This, however, is not a solution, as any time I use my vpn or connect my laptop to the work network, it happens all over again. I too don't understand the bug (haven't even tried yet, as I have too many other new annoyances since the switch from Unity on 17.04 to Gnome on 17.10). But that's an answer that addresses your (or others coming later) problem without a reboot.