Sometimes resolv.conf that is located at /etc/resolv.conf can be a headache. One way to manage the file is by using resolvconf package, which is I am.

The Problem

In my case, somehow resolv.conf appending these values at the end

nameserver 127.0.0.1
search ovh.net

I have set /etc/resolvconf/resolv.conf.d/head and /etc/resolvconf/resolv.conf.d/tail according my like but after restarting resolvconf, those lines keep coming back at the end of the file.

Solution

After a bit of digging, turned out I need to clear out the value inside /run/resolvconf/interface/original.resolvconf

nameserver 127.0.0.1
search ovh.net

You can just simply deleting /run/resolvconf/interface/original.resolvconf or just delete all content inside the file, or just commenting them by putting # infront of those lines

# nameserver 127.0.0.1
# search ovh.net

Then restart resolvconf and you are good to go.