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MX Lookup: Check the Mail Servers of a Domain

This free MX lookup shows which mail servers accept email for a domain. It lists each MX record in priority order, resolves the server to its IP addresses and flags common mistakes.

By Debmedia Technologies LLP · Kolkata, India · Updated

What Is an MX Lookup?

An MX lookup shows which mail servers are responsible for receiving email for a domain. MX stands for mail exchanger. When someone sends a message to you@example.com, their server performs this lookup to find where to deliver it.

If your email is bouncing, delayed or going to the wrong provider, the MX records are the first place to look. This tool lists them in the order they are tried and checks that each one works.

How to Use This MX Lookup Tool

  1. Enter the domain that receives email, for example example.com.
  2. Pick a resolver and press Lookup MX.
  3. Read the table: priority, mail server name, TTL, IP addresses and a check result.
  4. Fix any row marked with a warning, then run the lookup again.

How MX Priority Works

Each MX record carries a priority number. Senders try the lowest number first. If that server cannot be reached, they move to the next one. Records with the same number share the traffic.

PriorityMail serverRole
10mail1.example.comPrimary server, tried first
20mail2.example.comBackup, used if the first fails
30mail3.example.comSecond backup

The actual numbers do not matter, only their order. Hosted providers such as Google Workspace or Microsoft 365 give you the exact values to use.

What the Check Column Tells You

  • OK. The mail server name resolves to an IP address.
  • No address found. The target has no A or AAAA record, so senders cannot reach it.
  • Points to a CNAME. MX targets should have address records of their own. The SMTP standard, RFC 5321, expects a host name that resolves to an address.

Common Email Delivery Problems

Mail goes to the old provider

After moving email, old MX records may still be cached. Remove the old records completely and wait for the TTL to expire.

No MX records at all

Senders may try the domain’s address record as a fallback, but this is unreliable. Always publish explicit MX records for any domain that should receive mail.

Mail arrives but is marked as spam

Receiving and sending are separate. Check the sender policy tool and the signature key tool so receivers trust your outgoing mail.

Next Steps

After you fix the MX records, confirm the change with the email policy checker and review the rest of the zone with the record viewer. Keep the lookup handy whenever you change email providers.

When to Run an MX Lookup

Run an MX lookup whenever you change email providers, set up a new domain or investigate missing mail. It takes seconds and shows exactly where the world is sending your messages.

Frequently Asked Questions

An MX record names a mail server that accepts email for a domain. Several records can exist, each with a priority number, to give backup servers.
The lowest number is tried first. If that server is unreachable, senders try the next higher number. Equal numbers share the load.
No. An MX record must point to a hostname that has an A or AAAA record, and that hostname should not be a CNAME. The tool warns when it finds this.
Senders may fall back to the domain address record, but that is unreliable. Publish proper MX records for any domain that should receive mail.

Disclaimer: results come from live requests and can change as records and servers change. We cannot guarantee that every answer matches what every visitor sees.