Run a mail server lookup on any domain: see its MX records, and find the email host behind them.
Enter a domain, or an address to read the domain from.
Resolving MX records and identifying the mail host…
MX (Mail Exchange) records are DNS entries that specify which mail servers are responsible for handling email for a domain. When you send an email to [email protected], the mail system looks up the MX records for example.com to find out where to deliver the message.
Every email domain must have valid MX records configured to receive emails. Without MX records, email delivery fails and messages bounce back to the sender. MX records also specify the priority or preference of multiple mail servers, allowing redundancy and load balancing.
Understanding MX records is essential for email administrators, developers, and anyone troubleshooting email delivery issues. This free MX lookup tool gives you instant visibility into any domain's mail server configuration.
Every mail server lookup runs a full MX record and DNS check on the domain you enter.
Verifies that the domain has valid MX records configured.
Shows the priority/preference of mail servers.
Confirms that DNS can resolve the domain.
Checks if domain is valid and properly registered.
MX record verification is critical for reliable email delivery.
Without properly configured MX records, any email sent to the domain bounces back. Valid MX records are a prerequisite for email delivery.
Domains without MX records or with misconfigured records are often abandoned, parked, or no longer in use. This helps identify invalid domain addresses.
MX record lookups reveal which email service provider a domain uses (e.g., Google Workspace, Microsoft 365, custom mail servers).
MX lookups confirm that your domain is properly set up to receive emails after registering or migrating email services.
Mail server and MX record lookups help with critical email processes.
An email hosting lookup answers a different question than a plain DNS query. You rarely want the raw record — you want to know who is on the other end. A domain's MX records are a fingerprint: aspmx.l.google.com means Google Workspace, *.mail.protection.outlook.com means Microsoft 365, *.pphosted.com means Proofpoint sits in front of the real mailbox.
This mail server lookup reads that fingerprint for you. Alongside the records themselves you get the email host behind the domain — Google Workspace, Microsoft 365, Zoho, Fastmail, Proton, Amazon SES, Mailgun and others — plus any enterprise security gateway layered on top.
Knowing the mail provider changes what you do next. Google and Microsoft domains behave predictably. A domain sitting behind Proofpoint, Mimecast or Barracuda is filtering hard, which matters before you run cold outreach. And a domain whose MX host serves thousands of throwaway addresses is almost certainly a disposable email provider, whatever the domain name suggests.
To check whether an individual mailbox on that host actually exists, use the free email checker — MX records tell you the domain can receive mail, not that a specific address does. For programmatic access to the same data, see the email validation API.
Confirm that your domain's MX records are correctly configured after registering or updating email services.
Troubleshoot why emails are bouncing or not being delivered to a domain.
Check if email addresses are deliverable before sending marketing campaigns or bulk emails.
Regularly check your domain's MX records to ensure email service remains properly configured.
A normal MX record lookup goes one way — you give it a domain, it gives you a mail server. The reverse question is more useful and almost nobody answers it: given a mail server, which domains sit behind it, and what are they?
We profile the mail servers themselves. For each one you get the number of domains it handles, how many of those are throwaway addresses, and a sample of the domains. A hostname serving nine thousand domains at a 60% disposable rate tells you something about every message arriving from it — before you have looked at a single address.
Looking up a domain rather than a server? Every domain we profile gets a full report — MX records, mail provider, SPF and DMARC status, domain age and a trust score. Start from the disposable email provider catalogue or read how we classify a domain.
Domain profiles updated most recently. Each one carries MX records, the mail host, authentication status and a trust score.
MX lookup is one signal of many. The full suite combines MX, SMTP, catch-all, gateway detection, and domain trust into one verdict.
What you unlock
Each one answers a different question about the same DNS. Pick by the question you have.
Verify mail server configuration for any domain. No signup required. Unlimited free lookups.