Keith,
The DNS component is a performance issue, nothing more. And there are
TWO separate and /unequal /parts to the equation:
- In the first part, we're talking about making the DNS entries that
point other MAIL servers to your QMAIL server.... and in this part, you
honestly do not care whether it is your own personal DNS server, or your
ISP's (or registrar's) DNS server -- so long as you can make the SPF,
DomainKeys, and/or DKIM entries for SPAM control.
- It's the second part that is usually installed locally and can "make
or break" your QMAIL service. This is the part that resolves DNS queries
for the QMAIL server (determines the MX records for outbound mail,
checks for SPF records, etc.)
Thus, for a SMALL installation (one or two domains, only a handful of
users), using an "outside" DNS server will be fine... It will work,
albeit less than optimally. But as you grow your installation, you'll
start to see problems that will trace back to "slow DNS resolution"....
IMHO, and from what I've read: small-to-mid sized installations can use
BIND (www.isc.org) just fine -- but even that eventually "bogs down" as
the utilization curve ramps up -- which is why the QMT recommends the
use of DJBDNS (http://cr.yp.to/djbdns.html).
Now don't get me wrong -- DJBDNS is not the end-all, be-all of DNS
servers. In fact, I personally use BIND myself (currently about 30
domains, about 150 users - I consider myself a SMALL server). IMHO, BIND
is (and remains) the "gold standard" in being a DNS "server" -- but the
DJBDNS system is amazingly fast at being a DNS "client" (or, more
correctly, doing recursive lookups), and THAT is the component that the
QMAIL system needs to access -- and to access quickly (and repeatedly)
in larger environments.
Finally, I have to throw in one "jab" at the "think in the small,
confined box" types out there. Just because you need a DNS "server" on
your QMail box doesn't mean it has to be "THE" DNS server at your site.
Remember, the "DNS burden" of the QMail (or any other mail) system is in
the lookups, not in the responses to outside clients. So don't be afraid
to run QMail with its own DJBDNS service and have your "real" DNS
servers somewhere else...
So, to summarize -- especially for testing, you can leave your
resolv.conf pointing to your ISP's (or registrar's) DNS server and
everything should work just fine... but when you are truly ready to go
into production, you should implement either BIND or DJBDNS on the host
system. I've given you rationale and backup for either decision, so it's
a matter of taste now...
Enjoy your testing... and leave the DNS for later!
Regards,
Dan McAllister
IT4SOHO
On 4/26/2011 8:37 AM, Keith Smith wrote:
Hi,
Thank you for your help with this question.
I am doing an install of Qmail Toaster on CentOS 5.6 using the
documentation located at
http://wiki.qmailtoaster.com/index.php/CentOS_5_QmailToaster_Install
This is a test run to learn so I can do this in a production environment.
The docs say I need a DNS server. I am using my registrar's DNS. Do
I still need Bind or djbdns?
Thank you for your help!
--
Keith Smith Internet Marketing LLC
(480) 272-9268
PHP Programming Services
Search Engine Optimization
