What is an MX record in DNS?
A mail exchanger record (MX record) is a type of resource record in the Domain Name System (DNS) that specifies a mail server responsible for accepting email messages on behalf of a recipient's domain, and a preference value used to prioritize mail delivery if multiple mail servers are available. The set of MX records of a domain name specifies how email should be routed with the Simple Mail Transfer Protocol (SMTP).
- Zone File: This is where all the DNS records are stored for a domain.
- Host Record: This is the domain or subdomain you wish to use. The @ symbol is used to indicate the root domain itself. In our example the Host Record 'ftp' would be for the subdomain ftp.google.com and '@' would be google.com itself.
- Points to: This is the destination server that the domain or subdomain is sending the traffic to.
- TTL: The 'time to live' value indicates the amount of time the record is cached by a DNS Server, such as your Internet service provider. The default (and lowest accepted) value is 14400 seconds (4 hours). You do not normally need to modify this value.
- Action: This allows you to modify or remove existing records.
- Weight: This is similar to priority, as it controls the order in which multiple records are used. Records are grouped with other records that have the same Priority value. As with MX Entries, lower numbers are used before higher numbers.
- Port: This is used by the server or computer to process traffic to specific services, ensuring that all traffic comes through the door that it's expected on.
- Target: This is the destination that the record is sending the traffic to. This record would send traffic from service.example.com to listerning.otherexample.com over port 5060. SRV records generally require advanced knowledge of server administration to use.