Glue Records
Many people have often wondered why they can't run a DNS server for their own
.com/.net/.org/etc domain on a dynamic IP. It seems to simple to enter
yourname.dyndns.org as the DNS server in your registrar's form, and
yet if you do that you'll destroy yourname.dyndns.org's
functionality entirely. Others have wondered why, days after changing their
delegation to point to our servers, their domain still resolves to an IP other
than the one they see in the Custom DNS. The answer to both of these questions
involves glue records.
As you know from reading Anatomy of a
DNS Query, when DNS servers return a referral, they return other DNS
servers' names. This can lead to a following dilemma, which we'll illustrate
with an example: if you're trying to resolve yourname.dyndns.org, the
.org servers will tell you to ask ns.dyndns.org,
ns2.dyndns.org, ns3.dyndns.org, ns4.dyndns.org or
ns5.dyndns.org. However, in order to ask these servers about
yourname.dyndns.org, you need their IPs, which you can obtain by doing
a DNS query... but, to get the IP for ns.dyndns.org (or any of the
other four), you need to ask ns.dyndns.org, ns2.dyndns.org,
ns3.dyndns.org, ns4.dyndns.org, or ns5.dyndns.org,
which you can only get by querying them, etc. This creates a small
chicken-and-egg problem, obviously. Glue records are the solution.
What Is a Glue Record?
You can learn more about Glue Records and their role in the Domain Name Service by reading the KB article entitled What is Domain Registration?