DNS / BIND Server Configuration in RHEL 6 / CENTOS 6

What is DNS?

DNS is called as Domain name system. DNS is name resolution service which resolves human friendly name (such as Example Web Page) into IP address (192.168.0.10) DNS is a hierarchical distributed database that contains resolving of domain name into IP address.

Why DNS?

Because people and applications try to connect the network computer by specifying name. DNS has superior scalability, security and compatibility with internet.

Different types of DNS servers are:-

1. 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.

2. Secondary 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.

3. 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.

4. Stub servers

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.

5. Forwarders

Forwarders are 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. Here we are going to set up a Primary DNS server on a RHEL 6 / CENTOS 6 server. Scenario

This is the setup of a typical organization Example.com. It consists of web server, mail server, and ftp server on the internal network. The internal network uses 192.168.1.0/24 IP addressing scheme. We need to set up a primary DNS server that is best suited for my network.

I used a RHEL 6 x86_64 bit server to host the DNS server named rhel6.example.com. The server has two network card eth0 and eth1 which are connected to internet and internal network respectively.

Configuration Steps are working in progress!