Mail servers of a domain by priority, with addresses, and whether it can receive email
Runs in your browser. Only the lookup you start is sent to cloudflare-dns.com or dns.google; nothing else leaves your device. Updated on 18 Oct 2026.An MX lookup lists the servers that receive email for a domain, lowest preference number first, since senders try those first. Each server shows its IPv4 and IPv6 addresses, and one line says whether mail can be delivered, including the 2 special cases: no MX at all, and a null MX.
Type the domain, such as gmail.com, in Domain or email address.
Press Look up to fetch the MX records and the addresses of each mail server.
Read the Pref., Mail server, IPv4, IPv6 and TTL columns; the lowest Pref. is tried first.
Read the line above the table that says whether the domain can receive mail, then press Copy result.
Type a domain, or paste a whole email address, and this MX lookup asks a public resolver for the domain's MX records. They come back sorted the way a sending server uses them: lowest preference first, with equal preferences shared at random (RFC 5321 section 5.1). For each mail server the page then looks up its A and AAAA records, because a server name with no address cannot receive anything.
The verdict lines are the part people usually want. "Can receive mail" means every listed server has an address. If some do not, senders skip them and the page says how many. Two cases trip people up:
The page also flags an MX that names an IP address instead of a host, and an MX that points at an alias (CNAME), which RFC 2181 says it must not do.
The domain you type is sent to the resolver you choose, Cloudflare or Google, to answer it; nothing else leaves your device. The tool reads DNS only. It does not connect to the mail servers, so it cannot say whether they accept a message, offer STARTTLS or are on a blocklist; checking those needs a server that can open an SMTP connection, which a browser cannot do.
Type the domain, or paste an email address and the part after the @ is used. The MX records list every server that takes delivery, lowest preference number first, with each server's addresses. The names often show the provider: google.com for Google Workspace, outlook.com for Microsoft 365.
Senders try the lowest number first and move to higher numbers only when every server at the lower level fails. Servers with the same number share the mail at random. The numbers themselves carry no meaning beyond their order, so 10 and 20 behave exactly like 1 and 2.
Yes, sometimes. RFC 5321 says a domain with no MX but with an A or AAAA record is treated as its own mail server, an implicit MX. Mail then goes straight to that address, which works only when a mail server listens there. A domain with neither cannot receive mail.
A null MX is a single MX record of preference 0 pointing at a lone dot, written 0 followed by a period. RFC 7505 defines it as a statement that the domain accepts no email. Senders reject messages to it immediately instead of queueing them and retrying for several days.
Only to the public resolver you pick, Cloudflare at cloudflare-dns.com or Google at dns.google, because the resolver needs the name to answer. The lookups run from your browser; this site never receives the domain, and nothing else about you leaves your device.
No. A browser can ask DNS questions over HTTPS but cannot open the SMTP connection a real test needs, so the page cannot check that a server accepts mail, supports STARTTLS or is blocklisted. The verdict covers only what DNS says: which servers exist and whether they have addresses.
Still stuck? Ask about MX Lookup and anybody who knows can answer. No account needed.
Also works as: Email Server Lookup.
Same job, other tools: NS Lookup – Find the name servers a domain is delegated to, and how long resolvers cache them · AAAA Record Lookup (IPv6) – Check whether a domain has an IPv6 address, and what it is · DNSKEY Lookup – List a zone’s DNSKEY records with key tags, KSK or ZSK roles, algorithms and key sizes · AS Number Lookup – Turn an AS number into the network name, registry and allocation date · IP to ASN Lookup – Map an IP address to the ASN that announces it, with the BGP prefix.
On the related tools: Open Port Checker – See if a port forwarded on your router is reachable from the internet.