MX lookup: find the mail servers of any domain
Enter a domain to see its MX records in priority order, the IP address behind each mail server and whether its reverse DNS is set up.
| Priority | Mail server | IP address | Reverse DNS (PTR) |
|---|
MX is only the first step. See SPF, DKIM, DMARC, the TLS certificate and blacklists for this domain, or paste up to 25 domains at once.
What an MX lookup tells you
MX (mail exchanger) records say which servers accept mail for a domain. When someone sends to you@example.com, their server looks up the MX records of example.com and delivers to the one with the lowest priority number that answers.
| Column | What it means | Watch out for |
|---|---|---|
| Priority | Lower is tried first; equal numbers share load | A backup MX with weaker spam filtering |
| Mail server | The hostname the MX points to | An IP address or a CNAME instead of a hostname |
| IP address | Where that hostname resolves | No address at all: mail bounces |
| Reverse DNS | The PTR name of that IP | Missing, or not resolving back to the same IP |
Example MX records
example.com. 3600 IN MX 10 mail.example.com. example.com. 3600 IN MX 20 backup.example.net. mail.example.com. 3600 IN A 203.0.113.10
New to this? Read what an MX record is and how MX priority works.
Questions
How do I look up the MX records of a domain?
Type the domain above and press Look up MX. You get every mail server in priority order, its IP addresses and the reverse DNS of each IP. On the command line the same is dig MX example.com or nslookup -type=mx example.com.
What does the MX priority number mean?
Lower numbers are tried first. Servers with the same number share the load. If the preferred server does not answer, the sending server tries the next one and keeps retrying for up to several days.
Why does reverse DNS matter for an MX server?
Receiving servers check that the IP of a mail server has a PTR record and that the name resolves back to the same IP. A missing or mismatched PTR is a common reason for mail from that server landing in spam.
What does "mail is only forwarded" mean?
The MX points to a forwarding service such as Namecheap, Porkbun or ImprovMX. Incoming mail is passed on to another mailbox, but replies sent from that address will fail SPF unless you send through the same provider.
Can I look up MX records for many domains at once?
Yes. The free mail health checker takes up to 25 domains per run and also checks SPF, DKIM, DMARC, the TLS certificate and blacklists.
More free tools: Mail health checker · DMARC checker · SPF checker · DKIM checker
Run 10, 30 or 100 domains?
MXDeck is a Mac email app with these checks built in: one inbox for every contact@, and a red dot the day a domain’s mail breaks.