All about BIND DNS Server

By on October 23rd, 2015

 

BIND which stands for “Berkely Internet Name Domain” is software which is widely used in Linux servers for translating Domain names to IP address. Severs in which bind is Installed is called DNS server. BIND is open source software that allows you to publish your domain name to the Internet. We will get the installation package from the official website www.bind.org and then you can set up your own DNS server for your public network which is mainly internet and private network for LAN.

BIND is the most reliable DNS server program and the majority of DNS servers are based on BIND. The installation process of bind is very easy which actually includes the steps like downloading the compressed package and untaring it and you can compile it based upon the instruction given along with the download, compiling would be different based on the type of Linux distribution and version or you can even install using yum.

# yum install bind

# service named start

In cPanel or Webuzo servers bind can installed during the initial setup.

The default port Number for the named service 53 (TCP/UDP).

 

Brief on Zones and Domains

To make it simple Name servers will serve with the domains IP address. In Nameservers there would be many zones files in which it contains the information of the part of the domain name. Zone files are located in the location /var/named. In this location, there would be many zone files which are mainly named like

  • Domainname.db (eq test.com.db)
  • ADDR.db (192.168.0.db).

The files zone files in which of the type Domainname.db is actually used for Domain name to IP address mapping which is known as Forward mapping and this file includes the information of the domain and to which IP is pointed to. The files which are of the type ADDR.db is used for IP address to name lookup known as reverse mapping.

The “db” indicates database and collection of all the db that is both Domainname.db and ADDR.db is called Zone data files. There would be addition zone files rather than the above which is mainly created during the BIND installation and they are

  • named.ca
  • named.local & localhost.zone.

The named.ca contains the information of the root servers and the named.local & localhost.zone are used to create loopback (127.0.0.1)which is to direct traffic to its own server. The name server will link all these zone files on its configuration file which is located in the location /etc/named.conf. The configuration file contains the information of all the domain zone files are located.

 

DNS Records

Now we are going to discuss about the DNS resource records which are used in the zone files. They are mentioned in the following.

  • SOA record – This record is used to Indicates authority for this zone.
  • NS record – It will list a name server for this zone
  • MX record – Used to Indicate the mail exchange server for the domain
  • A record – To which IP the domain name is pointed to ie domain to IP Address mapping
  • CNAME record – Setting Canonical name for domain ie setting an alias for a domain
  • PTR record – This record is used to Point Address to the domain name which addresses to name mapping, used in ADDR.DB.

 

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