Mx (mail exchanger)
MX (Mail Exchanger) records!
In the Domain Name System (DNS), an MX record is a type of resource record that specifies the mail server responsible for accepting email messages on behalf of a domain name. In other words, it's like a "mail forwarding" instruction that tells the world where to send email messages intended for a particular domain.
Here's a breakdown of the MX record:
Format: MX preference TTL mail server
MX: The type of record (Mail Exchanger).preference: A numerical value that indicates the priority of the mail server. Lower values have higher priority.TTL: The Time To Live, which specifies how long the record is valid.mail server: The hostname or IP address of the mail server responsible for accepting email messages.
How it works:
- When an email client (e.g., Gmail, Outlook) wants to send an email to a recipient with a specific domain (e.g., example.com), it performs a DNS lookup to find the MX record associated with that domain.
- The DNS server returns the MX record, which specifies the mail server responsible for accepting email messages for that domain.
- The email client then sends the email to the specified mail server, which is responsible for delivering the message to the intended recipient.
Example:
Suppose we have a domain called example.com with two mail servers: mail1.example.com and mail2.example.com. We want to prioritize mail1.example.com as the primary mail server. We would create an MX record with the following values:
MX 10 3600 mail1.example.com
MX 20 3600 mail2.example.com
In this example:
MX 10indicates thatmail1.example.comhas a higher priority (lower value) and should be tried first.MX 20indicates thatmail2.example.comhas a lower priority (higher value) and should be tried only ifmail1.example.comis unavailable.3600is the TTL, which specifies that the record is valid for 1 hour.
By specifying multiple MX records with different priorities, you can create a backup mail server or distribute email traffic across multiple servers.