What Are MX Records?

MX (Mail Exchange) records are DNS records that specify the mail servers responsible for receiving emails for a domain. When someone sends an email to an address on your domain, the sender's mail server queries the MX records to find out where to route the email.

MX Record Priority

Each MX record has a priority value (also called preference). Lower numbers have higher priority. Multiple MX records allow for mail server redundancy:

• Priority 10 - Primary mail server (tried first)
• Priority 20 - Secondary mail server (tried if primary fails)
• Priority 30 - Tertiary mail server (tried if primary and secondary fail)

Common MX Record Examples

Domain	MX Priority	Mail Server
gmail.com	5	gmail-smtp-in.l.google.com
outlook.com	10	outlook-com.olc.protection.outlook.com
yahoo.com	1	mta5.am0.yahoodns.net
your-domain.com	10	mail.your-domain.com

How MX Record Lookup Works

1. Enter a domain name
2. The tool queries the DNS servers for MX records
3. Results show all mail servers for that domain, sorted by priority
4. Lower priority numbers are tried first for email delivery

Why Check MX Records?

• Email Troubleshooting - Check if mail servers are configured correctly
• Email Verification - Verify a domain accepts email
• Security - Identify legitimate mail servers for a domain
• Email Migration - Update mail server records when changing email providers
• Spam Assessment - Verify mail server configuration

MX Record Format

Domain: example.com
MX Record:  10  mail.example.com
           ^    ^
        priority mail server
                

Important Notes

• Every domain must have at least one MX record to receive email
• If no MX records exist, some systems will use A records for mail delivery
• Multiple MX records provide email redundancy
• MX records point to hostnames, not IP addresses directly
• Mail servers should have reverse DNS (PTR) records configured