What an MX record is
An MX record, short for Mail Exchange record, tells the internet where to deliver email for a domain. When a server wants to send a message to you@example.com, it looks up the MX records for example.com to find the hostnames of the receiving mail servers.
How priority works
Each MX record carries a priority number. Lower numbers are tried first:
- An MX of
mail1.example.comwith priority10is the primary target. - An MX of
mail2.example.comwith priority20acts as a backup.
If the primary server is unreachable, the sender falls back to the next priority. Multiple records at the same priority let mail spread across several servers.
Why it matters
Without correct MX records, a domain cannot reliably receive email, even if its website works fine, because web traffic and mail traffic use entirely separate records. Switching email providers means updating the MX records to point at the new provider's servers. MX hostnames must resolve to addresses through A or AAAA records, so the chain stays intact. For example, a domain using a hosted email service might set its MX to that provider's servers. You can check a domain's mail servers with the WhatIP mx-lookup tool.