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MX Lookup
Find MX records of a domain with priority and mail server diagnostics
usage:
mx-lookup --domain What is MX Lookup?
MX Lookup is a tool that queries the MX (Mail Exchange) records of a domain to identify the mail servers responsible for receiving email. It shows the priority of each server, allowing you to diagnose email delivery issues and verify the correct configuration of email routing.
Frequently Asked Questions
What are MX records? +
MX (Mail Exchange) records are DNS records that specify which mail servers are authorized to receive email for a domain. Each record has a priority value: the lower the number, the higher the priority.
Why is my domain not receiving email? +
The MX record might be missing or pointing to an unreachable server. Use MX Lookup to verify that the records are correctly configured and that the servers respond.
How many MX records can I have? +
There is no technical limit. It is best practice to have at least 2 with different priorities to ensure redundancy: if the primary server is offline, mail is routed to the secondary.
What does priority mean in MX records? +
The priority (or preference) is a number indicating the order in which mail servers are used. The server with the lowest number is contacted first. If unavailable, the next one is tried.
Can I use an IP instead of a hostname in an MX record? +
No, according to RFC specifications, an MX record must point to a hostname (FQDN), not directly to an IP address. The hostname must have a corresponding A record.
How do I verify if my MX records work? +
Use MX Lookup to find the servers, then verify connectivity with SMTP Diagnostics to test that they respond correctly on port 25/587.