Previously, I answered an question on superuser to create a subdomain. So I want to share my knowledge on DNS to everyone who would like to configure their DNS on purchased domain. DNS means domain naming server, system or service. The most basic server that is used worldwide is BIND (Berkeley Internet Naming Domain). Now basic purpose of DNS server (port 53) is conversion of name to IP. This conversion is important to make computer understand in its own language. Each domain normally has a zone file which is edited by DNS manager system of any registrar or hosting website. The main records in DNS are HOST A This record enables to provide name for IP address. new subdomains can be created using this record. SUBDOMAIN CLASS RECORD TYPE PROIRITY IP ADDRESS www IN A 10 192.168.1.1 @ IN A 10 192.168.1.1 MX (mail exchanger) It is a mail record required to notify query of mail server of domain. It is not necessary for an sender to only go to an IP of the domain l...