DNS Record (Resource Record) is the basic data element in DNS. It allows the DNS server to convert name request into IP addresses that specifies where on the Internet the server is located. In these domain servers, different record types are used for different purposes.
Some commonly used DNS record types:
A Record / AAAA Record
An A (Address) record maps a hostname to an IP address. The AAAA Record, is very similar to an A record. It is also associate a domain name with the IP address. However, these records are used to specify an IPv6, while A records are used to specify an IPv4.
A CNAME (Canonical NAME) record maps an alias name to another hostname which is in turn mapped to an IP address by an A record.
An MX (Mail exchanger) record specifies the hostname that will process incoming email for a domain.
An SOA (Start of Authority) record specifies authoritative information about a DNS zone. It is the DNS server that has the most authority to make changes in the domain or answer questions regard to that.
SRV records relate to a particular service of the domain, like FTP, rather than a specific machine the way A or C-name records do.
A PTR (Pointer) record maps an IP address to a hostname.