DNS servers TYPES

Types of DNS server

Primary DNS server:

A primary DNS server is created when a primary zone is added. It is a DNS server which holds primary zones for a particular domain. Primary DNS server acts as the zone’s central point of update. Newly created zones are always this type.

We can deploy primary zones in one of two ways: as standard primary zones or primary zones integrated with Active Directory.

Standard Primary Zones:

A Standard primary zone is the only zone type that can be edited or updated because the data in the zone is the original source of the data for all domains in the zone. Updates made to the primary zone are made by the DNS server that is authoritative for the specific primary zone. Users can also back up data from a primary zone to a secondary zone.

AD integrated zones:

These are useful when we want to maintain zone information in the AD . zone is saved in the AD as a result when we back up AD we are also backing up zone information.
If it is a primary zone, zone is saved as a normal text file as a result we have to back up the zone separately, AD integrated zone is created when we install AD with a domain name.

Creating in AD integrated zone:

On DC
Open DNS
Right click on FLZ
New zone
Next – check the box store the zone
Next – specify zone name
Next – allow both – next – finish

Seconday DNS server:

It is a DNS server hosting a secondary zone is called as secondary DNS server. That
can be any number of secondary servers for a primary. If primary server is down
then a secondary server provides a name resolution in zone until the primary server
is available.

Caching only serves:

This type of DNS servers does not have any zones in it, and purely depends on
caching. They contain the information of what has been cached while resolving
queries. Caching-only servers do not host any zones and are not authoritative for any particular domain

When you need to minimize name resolution traffic across WAN links without increasing zone transfer traffic, install a caching-only server.

In fact, when you get your IP configuration from your ISP, You are probably getting the IP addresses of caching only servers. The ISP’s DNS server doesn’t need to worry about mapping your computer’s name to an IP address; it instead needs to resolve your requests for internet resources as quickly as possible.

By default, the DNS Server service acts as a caching-only server. Caching-only servers thus require little or no configuration.

To install a caching-only DNS server:

1.	Install the DNS server role on the server computer.
2.	Do not configure the DNS server (as you might normally) to load any zones.
3.	Verify that server root hints are configured or updated correctly.

Stub servers:

Redirect the requests to a server that can answer it

It is a DNS server hosting a stub zone. This kind of servers has a copy of a zone containing only a list of the authoritative DNS servers for its master zone. In my words Stub-Zones are “Dynamic Conditional Forwarders”. What a Stub-Zone does: it queries a server you specify for a list of NS-Records, so you’ve got a list of all name-servers responsible for a zone. Then it’ll query the server for the A-Records of the Name servers of the zone.

A stub zone is a copy of a zone that contains only those resource records necessary to identify the authoritative domain name system servers for that zone.

A stub zone is used to resolve names between separate DNS namespaces.

May be necessary when a corporate merger requires that the DNS server for two separate DNS name spaces resolve names for clients in both namespaces

A stub zone consists of :

The SOA record

NS Record

A Record

The IP address of one or more master servers that can be used to update the stub zone

Forwarder Server:

Forwarder is the process of resolving external queries using forwarders. It
reduces network traffic on WAN links. It acts as a firewall which provides a
layer of security from external network.

Single master replication and multi master replication

Zone transfer can be incremental IXFR, that is based on individual record changes, or a complete set of records can be transferred (AXFR).