How to Check MX Records for Any Domain
MX (Mail Exchange) records tell the internet which servers handle email for your domain. Misconfigured MX records are one of the most common reasons email delivery fails silently. Whether you are migrating to a new email provider, troubleshooting bounces, or auditing a domain, checking MX records is the first step.
Look up MX records instantly
Use our free MX Lookup tool to see every MX record for any domain, including priority values and resolved IP addresses.
Step 1: Understand What MX Records Do
An MX record maps a domain name to one or more mail servers. Each record has two parts: a priority value and a hostname. When someone sends an email to your domain, the sending server queries DNS for your MX records and connects to the server with the lowest priority number first.
A typical MX configuration looks like this:
example.com. IN MX 10 mail1.example.com.
example.com. IN MX 20 mail2.example.com.Step 2: Look Up MX Records for Your Domain
Enter your domain into the MX Lookup tool to retrieve all published MX records. Alternatively, you can use the command line:
dig example.com MX +short
# or
nslookup -type=mx example.comThe output shows each mail server and its priority. Verify that the hostnames match your email provider's documentation.
Step 3: Verify Priority and Failover
If you have multiple MX records, confirm the priority values are correct. Your primary server should have the lowest number (e.g., 10) and backup servers should have higher numbers (e.g., 20, 30). This ensures automatic failover if your primary server goes down.
Step 4: Check That MX Hostnames Resolve
An MX record that points to a hostname with no A or AAAA record will cause delivery failures. Use the NS Lookup tool or a DNS A record query to confirm each MX hostname resolves to a valid IP address.
Step 5: Validate Against Your Email Provider
Compare the MX records you found with the values recommended by your email provider. Common configurations include:
- Google Workspace: Five MX records pointing to
aspmx.l.google.comand alternates - Microsoft 365: A single MX record pointing to
yourdomain-com.mail.protection.outlook.com - Zoho Mail: Three MX records pointing to
mx.zoho.comand alternates
If the records do not match, update them in your DNS provider's control panel. After making changes, use the MX Lookup tool again to verify propagation.
Frequently Asked Questions
What happens if a domain has no MX records?
If a domain has no MX records, sending servers fall back to the domain's A or AAAA record for mail delivery. This is unreliable and may cause messages to bounce. Always publish explicit MX records for domains that receive email.
What does the MX priority number mean?
The priority (or preference) number determines the order in which mail servers are tried. Lower numbers have higher priority. If the primary server is unreachable, the sending server tries the next one in order.
How long does it take for MX record changes to propagate?
MX record changes typically propagate within 1 to 48 hours depending on the TTL value set on the record. Most changes are visible within a few hours, but full global propagation can take up to 48 hours.