How do MX records work?
How MX records work: • The mail transport agent (Sendmail, Postfix, Qmail, MS Exchange, etc.) looks up the MX record for the domain • For each of the records returned, the MTA (mail transport agent) looks up the IP for the names. • It will choose, at random, any of the MXes with the lowest priority number. • Should that server fail, it will try another server with the same priority number. • Should all MX records with a given priority number fail, the MTA will try sending email to any of the MX records with the second-lowest priority value. As an aside, do not have MX records point to CNAMEs.
