MX-Records (Mail exchange)

MX-records are used to specify the e-mail server(s) responsible for a domain name.

Each MX-record points to the name of an e-mail server and holds a preference number for that server.

If a domain name is handled by multiple e-mail servers (for backup/redundancy), a separate MX-record is used for each e-mail server, and the preference numbers then determine in which order (lower numbers first) these servers should be used by other e-mail servers.

If a domain name is handled by a single e-mail server, only one MX-record is needed and the preference number does not matter.

When sending an e-mail to "This email address is being protected from spambots. You need JavaScript enabled to view it.", your e-mail server must first look up any MX-records for "example.com" to see which e-mail servers handles incoming e-mail for "example.com".

This could be "mail.example.com" or someone else's mail server like "mail.isp.com".

After this it looks up the A-record for that e-mail server name to connect to its IP-address.

Do not point an MX-record to a CNAME-record. Many e-mail servers don't understand this. Add another A-record instead.

This record type is defined in RFC1035.