[Wylug-discuss] Tweaking resolv.conf with NetworkManager

[John Hodrien]

On Wed, 3 Aug 2011, Smylers wrote:

> I just wrote:
>
>> there. I wish to provide some 'search' domains in resolv.conf (for use
>> when trying to resolve a bare hostname).
>
> Solved it. For the benefit of anybody else interested (or searching the
> archives in the future), the file I wanted is: /etc/dhcp3/dhclient.conf
> and the magic line to insert is:
>
>  prepend domain-search "klonk.example.net", "zok.example.org";
>
> Then restart networking with:
>
>  $ sudo /etc/init.d/NetworkManager restart
>
> I'm still vaguely intrigued as to why the tail file wasn't working ... but
> much less so now that I've found a method that works.

Just a note that I'm sure you're aware of anyway, but adding too many search
domains here *can* have a performance impact.  At worst, it's even quite funny
how bad it can be.

search foo.com bar.com

Say I have a tool configured to use blah.foo.com as a machine.  What you
*can* end up seeing is:

AAAA lookup for blah.foo.com (not found)
AAAA lookup for blah.foo.com.foo.com (not found)
AAAA lookup for blah.foo.com.bar.com (not found)
A    lookup for blah.foo.com (found)

It's not uncommon to see these lookups even if you've not got IPv6 configured,
and appending a dot doesn't necessarily get honoured.

Throw in an LDAP setup where LDAP servers are discovered via SRV records, and
this can be *really* excessive.

jh