Commit e9eff470 authored by Alyssa Ross's avatar Alyssa Ross
Browse files

nixos/networking: don't add extra names to ::1 

From hosts(5):

> For each host a single line should be present with the following
> information:
>
>               IP_address canonical_hostname [aliases...]

With lines like "::1 localhost ahost.adomin ahost", we were saying
that the canonical name for "ahost" was "localhost", the opposite of a
canonical name.  This is why a second loopback address (127.0.0.2) is
used for hostnames with IPv4 — if they were put after "localhost" on
the 127.0.0.1 line, the same thing would happen.  With IPv6 we can't
do the same thing as there's only a single loopback address, so
instead the right thing to do is to simply not list the hostnames in
/etc/hosts, and rely on the myhostname NSS plugin, which will handle
this correctly.

(Note that the examples in hosts(5) also do not include IPv6 FQDN or
hostname entries.)
parent 4c43880b

nixos/modules/config/networking.nix

+0 −2
Original line number Diff line number Diff line
@@ -163,8 +163,6 @@ in 
        ++ lib.optional (cfg.hostName != "") cfg.hostName; # Then the hostname (without the domain)

    in {

      "127.0.0.2" = hostnames;

    } // lib.optionalAttrs cfg.enableIPv6 {

      "::1" = hostnames;

    };



    networking.hostFiles = let

nixos/tests/hostname.nix

+2 −0
Original line number Diff line number Diff line
@@ -62,6 +62,8 @@ let 
            fqdn_and_host_name

            == machine.succeed("getent hosts 127.0.0.2 | awk '{print $2,$3}'").strip()

        )



        assert "${fqdn}" == machine.succeed("getent hosts ${hostName} | awk '{print $2}'").strip()

      '';

    };