MX lookup.
Check the MX records for any domain and see exactly where its email lands. It's the fastest way to find a domain's email host — this free email host lookup resolves every mail server, sorts them by priority, detects the email provider (Google Workspace, Microsoft 365, Proofpoint, Mimecast, Amazon SES and 10+ more) and shows the underlying IPs.
No signup · runs in your browser · also try our DNS lookup, blacklist checker and SPF/DKIM/DMARC checker.
How to check your MX records in 3 steps
- 1
Enter the domain in the box above (e.g.
example.com) and click Look up MX. - 2
Read the priority order. The lowest number is your primary mail server; higher numbers are backups that only receive mail if the primary is down.
- 3
Confirm the provider matches what you expect. A surprise provider — or leftover old records — is a classic sign of split or misrouted mail delivery.
MX records for popular email providers
Not sure what you're looking at? Here's how the MX hostnames of the most common providers look, so you can recognise them at a glance.
| Provider | Typical MX hostname | What it means |
|---|---|---|
| Google Workspace | smtp.google.com (or aspmx.l.google.com) | Gmail for business |
| Microsoft 365 | <your-domain>.mail.protection.outlook.com | Exchange Online |
| ProtonMail | mail.protonmail.ch, mailsec.protonmail.ch | Encrypted mail |
| Zoho Mail | mx.zoho.com, mx2.zoho.com | Budget business mail |
| FastMail | in1-smtp.messagingengine.com | Independent mail host |
| Amazon SES (inbound) | inbound-smtp.<region>.amazonaws.com | App / transactional |
| Proofpoint | mxa-…/mxb-…pphosted.com | Security gateway in front of M365 |
| Mimecast | <domain>-com.mail.protection.mimecast.com | Security gateway |
What this tells you
MX priority order — receivers try the lowest priority number first. If you see two MXes at the same priority, mail is load-balanced between them. If the lowest priority is unreachable, mail tries the next one — that's how backup MX works.
Provider detection — most mail platforms put a recognisable signature in their MX hostnames. We match against known patterns for Google Workspace, Microsoft 365, ProtonMail, Zoho, Amazon SES, Proofpoint, Mimecast, Barracuda, MailRoute, FastMail and more — so you don't have to guess from a cryptic hostname.
Resolved IPs — the actual IPv4 addresses each MX hostname resolves to. Useful for blacklist checks, geographic-routing audits, and confirming what's really accepting mail for the domain.
No MX, but A/AAAA — the mail RFC says receivers should fall back to the apex A record if no MX exists. We surface that case explicitly so you know your domain is technically receiving mail through implicit-MX even without a published MX record.
Common MX problems we fix
An MX lookup often surfaces issues that quietly cost you email. The ones we see most:
No backup MX
A single mail server means mail bounces the moment it's unreachable. A secondary MX queues mail until you're back.
Leftover old records
Stale MX entries from a previous provider cause split delivery — some mail goes to the old host and disappears.
MX points to a listed IP
If a mail server's IP is blacklisted, inbound and outbound mail suffers. Check it on the blacklist tool →
No SPF/DKIM behind the MX
MX without aligned authentication invites spoofing. Run the SPF/DKIM/DMARC check →
Want your mail flow handled properly?
Edos Solutions designs, secures and monitors business email infrastructure for Australian organisations — backup MX, filtering, authentication and deliverability, done right.
Privacy
Lookups happen in your browser via Cloudflare's public DNS-over-HTTPS endpoint. Edos Solutions doesn't log the domains you check, doesn't run any analytics on this page, and doesn't capture your IP.
Frequently asked questions
- What is an MX lookup tool?
- An MX lookup tool checks a domain's MX (Mail Exchanger) DNS records — the records that tell the world which servers receive that domain's email. Enter any domain and this free tool resolves its mail servers, sorts them by priority, identifies the email provider (Google Workspace, Microsoft 365, ProtonMail, Amazon SES and more), and shows the underlying IP addresses. No signup, no limits.
- What is an MX record?
- An MX (Mail Exchanger) record is a DNS record that specifies which mail servers accept incoming email for a domain. When someone sends mail to user@yourdomain.com, the sending server looks up your MX records to find where to deliver the message. Without MX records, mail to your domain cannot be delivered.
- How do I check the MX records for my domain?
- Type your domain into the box above and click "Look up MX". This tool queries live DNS in your browser and returns every MX record, sorted by priority, with the email provider detected and each mail server's IP address — no command line or signup required.
- What does MX priority mean?
- Each MX record has a priority number. The sending server always tries the lowest priority number first. If multiple MX records share the same priority, delivery is load-balanced between them. Higher priority numbers act as backup — they only receive mail if the lower-priority servers are unreachable.
- How can I tell which email provider a company uses?
- Look at the MX hostname. Most major providers embed a recognisable string: Google Workspace uses aspmx.l.google.com, Microsoft 365 uses mail.protection.outlook.com, ProtonMail uses protonmail.ch. This tool detects over 20 major providers automatically. If the hostname is a custom domain, the company likely runs their own mail infrastructure.
- How do I find a domain's email host?
- Enter the domain above and run the lookup. An email host lookup works by reading the domain's MX records — the DNS entries that name the mail servers receiving its email. This tool resolves those records, then matches the hostnames against 20+ known providers (Google Workspace, Microsoft 365, ProtonMail, Mimecast and more) so you can find the email host in one step instead of decoding raw DNS by hand.
- What if no MX records are found for a domain?
- If a domain has no MX records but has an A record, the mail RFCs say senders should attempt delivery to the apex A record directly — this is called implicit MX. This tool surfaces that case explicitly so you know the domain is technically receiving mail even without published MX records. A domain with neither MX nor A records cannot receive email.
- Can a domain have multiple MX records?
- Yes, and most production domains do. Multiple MX records give you failover and load balancing: the priority number controls the order. Two records at the same priority share the load; records at higher numbers act as backups that only receive mail when the lower-priority servers are unreachable. A single MX record means a single point of failure.
- How do I read an MX record?
- An MX record has two parts: a priority number and a mail server hostname, written as "10 mail.example.com". The number is the preference (lower = tried first), and the hostname is the server that accepts mail. That hostname must itself resolve to an A/AAAA record — an MX pointing at a CNAME or a non-resolving host is invalid and breaks delivery.
- What's the difference between an MX record and an A record?
- An A record maps a hostname to an IP address. An MX record names which hostname(s) receive a domain's email and in what priority order — it never contains an IP directly, it points to a hostname that has its own A record. You can have a website (A record) and email (MX record) for the same domain pointing at completely different servers.
- How long do MX record changes take to take effect?
- MX changes propagate according to the record's TTL (time to live). Sending servers cache your old MX until the TTL expires — commonly 1 hour (3600s), sometimes up to 24 hours. Before a mail migration, lower the TTL a day or two ahead so the cutover is fast, then raise it again once delivery is confirmed on the new servers.
- Why does my MX point to a security gateway instead of my mailbox provider?
- When an email security gateway (Proofpoint, Mimecast, Barracuda, or a Linux gateway like Edos Mail Shield) sits in front of your mailboxes, your MX must point at the gateway so all inbound mail is filtered first. The gateway then relays clean mail to Microsoft 365 or your mail server. Seeing a gateway in your MX is expected and correct in that setup.