MX Record Checker
Find out where a domain receives its email. The checker lists every mail server in the order senders try them, resolves each one to its addresses and points out configuration errors that cause lost mail.
- Encrypted connection
- No sign-up
- Free to use
How to use MX Record Checker
- Enter a domain name, or paste an email address to use its domain.
- Select Check MX records.
- Read the verdict and the list of mail servers with their priorities and addresses.
- Review the checks, then follow the links to test SPF, DKIM and DMARC for the same domain.
MX Record Checker features
Servers in delivery order
MX records sorted by priority, exactly as a sending server would try them.
Addresses for each server
The IPv4 and IPv6 addresses behind every mail server name.
Provider recognition
Names the email service when the servers belong to a well-known host such as Google Workspace or Microsoft 365.
Configuration checks
Detects MX hosts that do not resolve, point to an alias or contain an IP address.
Null MX awareness
Recognises domains that declare they accept no mail, and domains with no MX at all.
SPF and DMARC at a glance
Shows whether the two key authentication records exist.
When to use MX Record Checker
- Verifying new MX records after moving a domain to another email provider.
- Finding out which email service a company uses.
- Investigating bounced messages that mention “no mail server” or “host not found”.
- Checking that a domain used only for a website does not accept mail by accident.
MX Record Checker FAQ
What is an MX record?
A mail exchanger record tells sending servers which hosts accept email for a domain. Each record has a host name and a priority number. Without MX records, mail for the domain has nowhere to go apart from an unreliable fallback to the domain's own address.
How does MX priority work?
The server with the lowest number is tried first. If it cannot be reached, the sender moves to the next lowest. Records that share a number are chosen at random, which spreads the load between them. The numbers themselves have no meaning beyond their order: 1 and 5 behave the same as 10 and 20.
How long do MX changes take?
As long as the TTL of the old records, typically between five minutes and a day. During that window some senders still deliver to the previous servers, so keep the old mailbox service running until the change has fully taken effect.
Can an MX record point to an IP address or a CNAME?
No to both. The target must be a host name that has its own A or AAAA record. An IP address is invalid syntax, and a CNAME target violates the mail standards; some senders tolerate it, others reject the mail.
What is a null MX?
A single MX record with priority 0 and a target of “.” (a dot). It tells the world that the domain does not accept email, so senders can fail immediately instead of retrying for days. It is the right choice for domains that never receive mail.
Does this test whether mail is actually accepted?
No. It reads DNS only and does not connect to the mail servers. A correct MX setup is necessary for delivery but does not prove that a given mailbox exists or that the server is accepting connections.
MX records and reliable email delivery
Every message sent to an address at your domain begins with an MX lookup. The sending server asks DNS for the domain's mail exchangers, sorts them by priority, resolves the first host name to an address and opens a connection. If any link in that chain is broken, the message is delayed or returned, often with an error that does not mention DNS at all.
The most common mistakes are simple. A typing error in the host name leaves an MX record that resolves to nothing. Old records from a previous provider remain next to the new ones, so part of the mail goes to a service that no longer has your mailboxes. A record points to an alias or to a raw IP address, which some senders accept and others refuse, producing failures that seem random. The checks on this page look for each of these.
Redundancy is often misunderstood. A second MX record helps only if it leads to a machine that can really accept your mail. With a hosted provider, a single name normally represents a large pool of servers, and one record is fine. A “backup MX” at a different provider that merely queues mail is frequently a weakness, because spammers target the secondary server, which tends to filter less strictly.
Receiving is half the picture. For mail you send to be trusted, the domain also needs SPF, DKIM and DMARC records. The checker reports whether SPF and DMARC exist; use the dedicated tools to examine them in detail.