Home / Email Tools / MX Lookup
Email Tools
Mail exchangers with priorities and resolved hosts.
MX Lookup retrieves the mail exchanger records for a domain, listing each mail server with its priority and resolved IP addresses so you can confirm where inbound mail is routed.
Enter a domain name (example.org) and run the tool. The probe queries the authoritative servers for MX records and resolves each mail host to its IP addresses.
Input: Domain — e.g. example.org.
Each line shows a mail server hostname with its priority (lowest = preferred) and the IP addresses it resolves to. Mail is delivered to the lowest-priority server first; higher-priority entries act as backups. A missing or misconfigured MX record means the domain cannot receive mail.
→ Confirm where inbound mail for a domain is routed.
→ Verify MX priorities before adding or removing a mail server.
→ Resolve mail host IPs to check IPv4/IPv6 coverage.
→ Diagnose mail delivery to a domain after a provider change.
Yes. MX priority is ascending — the lowest number is tried first. A priority 10 server is preferred over a priority 20 server, which only receives mail if the 10 is unreachable.
Technically yes — if there is no MX, mail servers fall back to an A/AAAA record for the apex. However, this is unreliable and not recommended; always publish explicit MX records for any domain that should receive mail.
Give backups a higher number than the primary so they are only used when the primary is down. Ensure backups do not accept mail for users they cannot deliver to, or they will generate backscatter.