We may want to use localhost to make it bind to both v4 and v6 sockets.
Created from redmine issue https://projects.theforeman.org/issues/28681
Upstream bug assigned to None
The default is 0.0.0.0, not 127.0.0.1. Anyway, it still binds to v4 only.
*** This bug has been marked as a duplicate of bug 1789006 ***