What is a DNS lookup?
A domain has a number of records associated with it, a DNS server can be queried to determine the IP address of the primary domain (A record), mail servers (MX records), DNS servers (NS nameservers) and other items such as SPF records (TXT records).
Types of DNS Records:
- A record: Address record maps a hostname to a 32-bit IPv4 address.
- AAAA record: IPv6 address record maps a hostname to a 128-bit IPv6 address.
- CNAME record: Canonical name record is an alias of one name to another.
- MX record: Mail exchange record maps a domain name to a list of mail exchange servers for that domain.
- PTR record: Pointer record maps an IPv4 address to the canonical name for that host. Setting up a PTR record for a hostname in the in-addr.arpa domain that corresponds to an IP address implements reverse DNS lookup for that address.
- NS record: Name server record maps a domain name to a list of DNS servers authoritative for that domain.
- SOA record Start of authority record specifies the DNS server providing authoritative information about an Internet domain.
- SRV record: It is a generalized service location record.
- TXT record: This record is used to implement the Sender Policy Framework.