Sending & delivery events
MX record
A DNS record that specifies which mail servers are responsible for receiving email on behalf of a domain, and in what priority order.
How MX records work
Each MX record names a mail server and a priority number. Sending servers try the lowest number first and fall back to the others if it’s unavailable. For example, a domain on Google Workspace has MX records pointing at Google’s servers.
MX records and sending
MX records control where mail to a domain is received, not where it’s sent from, so you don’t need to change them to send through an email platform. They still matter for sending in two ways: replies to your emails go to your MX servers, and many receivers distrust mail from domains with no MX records at all.
Checking a domain’s MX records
Our free MX lookup shows the servers a domain routes mail to, in priority order, which is useful for confirming a migration or diagnosing lost replies. MailCraft’s email validation also checks that a recipient’s domain has mail servers before you send.
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Full glossarySending & delivery events
MTA (Mail Transfer Agent)
The software that routes email between servers over SMTP — the underlying engine that actually delivers a message from sender to recipient.
Authentication
SPF (Sender Policy Framework)
A DNS TXT record listing which mail servers are authorized to send email on behalf of your domain. Receiving servers check it to catch spoofed senders.
Sending & delivery events
Hard bounce
A permanent delivery failure — the address or domain doesn’t exist. Hard bounces should be suppressed immediately and never retried.