Impact of having loghost defined in DNS...?
kcd at daimlerchrysler.com
Wed Dec 1 02:21:10 UTC 2004
Danny Mayer wrote:
> At 07:50 PM 11/30/2004, Kevin Darcy wrote:
>> >The usual recommendation is to add a localhost record to the domain
>> >so that the DNS will return the record faster, but it's not a
>> >DNS lookups otherwise take a little longer.
>> I think you haven't understood the previous poster's point. Some OS'es
>> (Solaris for sure) *intercept* the name "localhost" in the
>> system-resolver routines and resolve it to the loopback address,
>> *regardless* of what DNS resolves the name to and *regardless* of
>> whether or in what order DNS is used as a resolution mechanism. On such
>> boxes, it's totally pointless to define the name "localhost" in DNS,
>> since it'll never get queried. For that matter, it's pointless to define
>> it in /etc/hosts either. "loghost" is a different matter entirely.
> Then you missed my point. The nameserver isn't the only system
> that queries the DNS for localhost. There are plenty of systems
> out there that don't have it defined and end up going to the DNS
> for resolution. If you don't have it defined in the DNS it goes to
> the root servers and we really shouldn't be letting the DNS do that.
Not a problem here: I just checked and queries for "localhost" amount to
less than .003% of my total query volume. As for annoying the Internet
root servers, we have internal roots, so that's not a problem :-) Even
if we were forwarding towards the Internet, the 1-day negative caching
TTL would mean only 1 query per day for "localhost" per forwarder
(assuming no restarts or reboots).
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