MX Lookup
List a domain's mail servers in priority order.
Frequently asked questions
What is an MX record?
An MX (Mail Exchange) record tells other mail servers where to deliver email for your domain, and in what priority order.
What does MX priority mean?
Lower numbers are tried first. Servers with equal priority share load. If the primary is unreachable, senders fall back to the next-lowest priority.
What if a domain has no MX record?
Senders fall back to the domain's A record (an "implicit MX"). If there is neither, the domain cannot receive email.
Can I use a CNAME as an MX target?
No. The host named in an MX record must be a real host with an A or AAAA record, not a CNAME. Pointing an MX at a CNAME violates the DNS standards and can cause delivery problems.
What does a null MX record mean?
A single MX record of "0 ." (a null MX) explicitly declares that a domain does not receive email, so senders can reject mail immediately instead of falling back to the A record or timing out.
How many MX records should a domain have?
At least two pointing to independent mail servers is good practice, so mail still flows if one server is down. The priority values decide the order senders try them.
Do MX records affect where email is sent from?
No. MX records only control where inbound mail is delivered. Your outbound sending servers are authorized separately through SPF, and messages are signed with DKIM.