MX Lookup (2026): How to Find a Domain’s Mail Server and Fix Email Routing
Use MX lookup to find where email is delivered, understand MX priority, and troubleshoot common mail routing and verification issues.
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How to use MX Lookup
MX records control where a domain receives email. When MX records are wrong, emails bounce, verification fails, and support tickets pile up. MX lookup is the fastest way to confirm whether a domain is pointing to Google Workspace, Microsoft 365, a custom mail server, or something else.
Quick Answer
Run an MX lookup for the domain and confirm that the MX hostnames match your mail provider and that priorities are correct. If you recently changed providers, check DNS propagation and remove old MX entries.
What MX Records Do
MX stands for Mail Exchanger. An MX record points to a hostname that accepts email for the domain. Receivers deliver mail to the lowest priority number first (highest priority). If that host is unavailable, they try higher numbers next.
How to Run an MX Lookup
Use DNS Lookup and select MX record type, or use your MX-specific workflow. Confirm you see the expected values publicly. If you changed MX recently, use DNS Propagation Checker to see how different regions respond.
Common MX Problems
1) Mixed providers. You have MX entries for both Google and Microsoft. That can cause mail to route unpredictably.
2) Wrong priority ordering. Some admins accidentally set priority numbers incorrectly, causing a backup server to receive mail first.
3) Old MX still present. After migration, old MX can continue receiving mail if priorities allow it.
4) MX points to a non-existent hostname. If the hostname does not resolve, mail bounces.
Recommended Next Steps
Once MX routing is correct, complete email authentication for deliverability and security. Confirm SPF, DKIM, and DMARC are published as TXT records and aligned with your From domain.
- DNS Lookup to validate TXT records for SPF/DKIM/DMARC.
- DNS Propagation Checker when changes are new.
FAQ
Q: Do I need MX records for a website?
A: No. MX records are only for email reception.
Q: What priority should my main MX have?
A: Lower numbers are tried first. Providers usually specify the exact priority numbers to use. Follow their official documentation.
Q: Why does email bounce after changing MX?
A: Common causes are propagation delay, wrong values, or missing verification steps with the new provider.
Q: Can I point MX to an IP address?
A: MX must point to a hostname, not directly to an IP.
Q: How long does it take for MX changes to work?
A: It depends on TTL and caching. Many updates take minutes, but global consistency can take longer.
Q: Do SPF/DKIM/DMARC affect receiving mail?
A: They mainly affect sending and reputation, but misconfiguration can still cause confusion during migrations.