MX record
An MX record names a mail server for a domain. Its preference value orders possible destinations; it confirms neither a mailbox nor delivery.
What is an MX record?
An MX record is a DNS entry that names a mail server for a domain name. It also contains a preference value. RFC1035 specifies that lower values are preferred. The destination is a server name; the record does not contain a mailbox's contents.
Example: moving incoming mail traffic
A fictional company changes its email service. The team enters the mail servers specified by the new provider with the appropriate preference values. Before switching, the necessary mailboxes and acceptance of mail for the domain must also be configured at the provider.
The published MX mapping shows which destinations are intended to accept mail. It does not prove that a particular mailbox exists, a message was accepted or it reached the intended folder.
Problems are therefore investigated separately in DNS resolution and mail processing. Website addresses, sending permissions and protection of the mail connection are further configuration matters; the MX record alone does not govern them.
Sources
Related terms
- Domain Name SystemDNS supplies data about names, such as a web server’s address. Name resolution, the server connection and application behaviour are separate steps.
- DomainA domain is a named part of the DNS namespace. The name does not create a website; hosting, email and the application still need to be connected.
- TXT recordA TXT record stores text in DNS. The relevant procedure determines how a service interprets it, for example when checking control of a domain.
- Return-PathReturn-Path records the SMTP reverse path in a header. It explains the technical route for error reports, not a person’s identity.
- Envelope-FromEnvelope-From identifies the SMTP sender for transport and error feedback. It must be distinguished from the visible sender address.
- DMARC aggregate reportA DMARC aggregate report summarises a reporting mail system’s domain checks over a period. It helps examine sending sources and misconfigurations.
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