As Adam suggested, look at NetworkManager. For a static configuration, it would probably be best to make sure it's disabled. While it's not systemd-level invasive (cue sound of can of worms opening), it does tend to get its mitts on things it would be best if it didn't. It may be the thing for roaming clients, but not for servers that stay put on a fixed IP address.

On 2016-08-16 14:41, Kevin McGregor wrote:

Nope, static: iface eth0 inet static

It's a server, and we don't use DHCP for servers (alas). We're using dnsmasq locally on all servers solely for DNS resolution caching.

On Tue, Aug 16, 2016 at 2:36 PM, Gilbert E. Detillieux <gedetil@cs.umanitoba.ca mailto:gedetil@cs.umanitoba.ca> wrote:

Is this server setting its interface addresses manually, or is it
a DHCP client?  In the latter case, the DHCP server may be
specifying the domain search list, and the client side is happily
overwriting your /etc/resolv.conf on every lease renewal.

Gilbert

On 16/08/2016 2:14 PM, Kevin McGregor wrote:

    I'm running Ubuntu 14.04 on a particular server. In the
    /etc/resolv.conf
    there are two search lines:
    search domA.example.org <http://domA.example.org>
    <http://domA.example.org> domB.example.org
    <http://domB.example.org>
    <http://domB.example.org> # [NOTE I made these up, but the
    form is the same]
    search domA.example.org <http://domA.example.org>
    <http://domA.example.org>

    I want the search setting to be just:
    search domA.example.org <http://domA.example.org>
    <http://domA.example.org>

    I've deleted the top/offending line, but every time I restart
    dnsmasq or
    run resolvconf -u (for example), the offending line comes
    back. Where is
    it getting the domB.example.org <http://domB.example.org>
    <http://domB.example.org> from? I've
    looked in all the usual places (I think), and tried "grep -R
    domB *" in
    /etc, but nothing turns up! I'm at a loss.

    Any pointers on where I should look next?

    Thanks,
    Kevin