Filter
Top Products
• A need to delegate management of a DNS domain to a number of
organizations or departments within an organization
• A need to distribute the load of maintaining one large DNS database among
multiple name servers to improve the name resolution performance as well as
create a DNS fault tolerant environment
• A need to allow for host’s organizational affiliation by including them in
appropriate domains
The NS RRs facilitate delegation by identifying DNS servers for each zone. They
appear in all forward and reverse look-up zones. Whenever a DNS server needs to
cross a delegation, it will refer to the NS RRs for DNS servers in the target zone.
In the figure below, the management of the microsoft.com domain is delegated
across two zones, microsoft.com. and mydomain.microsoft.com.
com edu gov
...
microsoft
ftp
microsoft.com Domain
mydomain
ntserver
...
microsoft.com
Zone
mydomain.microsoft.com
Zone
Note: If multiple NS records exist for a delegated zone identifying multiple DNS
servers available for querying, the Windows 2000 DNS server will be able to select
the closest DNS server based on the round trip intervals measured over time for
every DNS server.
Replicating the DNS database
There could be multiple zones representing the same portion of the namespace.
Among these zones there are two types:
• Primary
• Secondary
Primary is a zone to which all updates for the records that belong to that zone are
made. A secondary zone is represented by a read-only copy of the primary zone.
Windows 2000 White Paper
7