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An added benefit is that, even if the administrators over at
example.net
change their
configuration, you won't have to do anything because the changes will automatically rep-
licate to the stub zone, just as they would for a secondary server.
Stub zones can also be useful when you administer two domains across a slow connec-
tion. Let's change the previous example a bit and assume that you have full control over
example.com
and
example.net
but that they connect through a 56Kbps line. In this case,
you wouldn't necessarily mind using secondary zones because you personally administer
the entire network. However, it could get messy to replicate an entire zone file across that
slow line. Instead, stub zones would refer clients to the appropriate primary server at the
other site.
GlobalName Zones
Earlier in this chapter, I talked about organizations using WINS to resolve NetBIOS names
(also referred to as
computer names
) to TCP/IP addresses. Even today, many organizations
still use WINS along with DNS for name resolution. Unfortunately, WINS is slowly
becoming obsolete.
To help organizations move forward with an all-DNS network, Microsoft Windows
Server 2012 R2 DNS supports
GlobalName zones
. These use single-label names (DNS
names that do not contain a suffix such as
.com
,
.net
, and so on). GlobalName zones are
not intended to support peer-to-peer networks and workstation name resolution, and they
don't support dynamic DNS updates.
GlobalName zones are designed to be used with servers. Because GlobalName zones are
not dynamic, an administrator has to enter the records into the zone database manually. In
most organizations, the servers have static TCP/IP addresses, and this works well with the
GlobalName zone design. GlobalName zones are usually used to map single-label CNAME
(alias) resource records to an FQDN.
Zone Transfers and Replication
DNS is such an important part of the network that you should not just use a single DNS
server. With a single DNS server, you also have a single point of failure, and in fact,
many domain registrars encourage the use of more than two name servers for a domain.
Secondary servers or multiple primary Active Directory Integrated servers play an integral
role in providing DNS information for an entire domain.
As previously stated, secondary DNS servers receive their zone databases through zone
transfers. When you configure a secondary server for the first time, you must specify the
primary server that is authoritative for the zone and that will send the zone transfer. The
primary server must also permit the secondary server to request the zone transfer.
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