MX Lookup
Check a domain’s MX records and mail provider, and test SPF, DMARC and DKIM in one go, with plain-English fixes.
Emails landing in spam, bouncing, or not arriving at all? The cause is almost always in your domain’s DNS. GoogieHost’s free MX Lookup checks every email record in one go: MX, SPF, DMARC and DKIM, plus MTA-STS, TLS-RPT and BIMI.
Enter a domain or an email address. The tool lists your mail servers and detects your email provider. It also counts your SPF DNS lookups against the limit of 10, explains every DMARC tag, and searches 30+ common DKIM selectors. Each problem comes with a plain-English fix.
What the MX Lookup Checks
| Record | What the tool shows |
|---|---|
| MX | Mail servers in priority order, their IP addresses, and the detected provider (Google Workspace, Microsoft 365, Zoho Mail and more) |
| SPF | The full record, every include expanded with its meaning, the total DNS lookups (limit 10) and policy problems |
| DMARC | The record, each tag explained, and whether your policy actually protects you |
| DKIM | Keys found for your selector, or a search of 30+ common selectors, with key type and size |
| MTA-STS, TLS-RPT, BIMI | Whether these optional security and branding records exist |
How to Use the MX Lookup Tool
- Enter a domain or email: For example example.com or you@example.com.
- Add a DKIM selector (optional): If you know it (e.g. google or selector1), enter it. Otherwise the tool tries common ones.
- Click Check Records: You get a Pass, Warning or Problem score for MX, SPF, DMARC and DKIM, with details below.
What Is an MX Record?
An MX (Mail Exchanger) record tells other mail servers where to deliver email for your domain. Each MX record has a priority: the lowest number is tried first, and higher numbers are backups. Without MX records, your domain can’t reliably receive email.
| Provider | Typical MX records |
|---|---|
| Google Workspace | smtp.google.com (or aspmx.l.google.com and alt1–alt4) |
| Microsoft 365 | yourdomain-com.mail.protection.outlook.com |
| Zoho Mail | mx.zoho.com, mx2.zoho.com, mx3.zoho.com |
| cPanel hosting | mail.yourdomain.com or yourdomain.com |
What Is SPF?
SPF (Sender Policy Framework) is a TXT record that lists which servers may send email for your domain. Receiving servers check it to spot forged senders. A typical record looks like v=spf1 include:_spf.google.com ~all.
- include: trusts another provider’s list, e.g. include:spf.protection.outlook.com for Microsoft 365.
- ip4: / ip6: trusts a specific IP address or range.
- a / mx: trusts your domain’s own web or mail server IPs.
- ~all (soft fail) marks other senders as suspicious; -all (hard fail) tells receivers to reject them. Never use +all.
The SPF 10 DNS Lookup Limit
SPF allows at most 10 DNS lookups while checking a message. Every include, a, mx, exists and redirect counts, including the ones nested inside other includes. Go over 10 and receivers return a PermError, which means SPF fails for all of your email, even from legitimate servers.
This is very common when a domain adds several services (Google Workspace, a newsletter tool, a CRM, a transactional email service). The tool counts nested lookups for you. To get back under the limit:
- Remove includes for services you no longer use.
- Replace a and mx with the actual ip4: addresses if they rarely change.
- Send marketing email from a subdomain (e.g. news.example.com) with its own SPF record.
- Use an SPF flattening service as a last resort, and keep it updated.
Also make sure you have only one SPF record. Two separate v=spf1 records also cause a PermError.
What Is DMARC?
DMARC tells receivers what to do when an email fails SPF and DKIM alignment, and where to send reports. It is a TXT record at _dmarc.yourdomain.com, for example v=DMARC1; p=quarantine; rua=mailto:dmarc@example.com.
| Policy | What happens to failing email |
|---|---|
| p=none | Delivered as normal; you only get reports (monitoring mode) |
| p=quarantine | Sent to the spam/junk folder |
| p=reject | Rejected outright; the strongest protection against spoofing |
The safe way to roll out DMARC: start with p=none and a rua address, read the reports for a few weeks to find every service that sends as you, fix their SPF and DKIM, then move to quarantine and finally reject.
What Is DKIM and How Do I Find My Selector?
DKIM adds a digital signature to every outgoing email. The public key is published at selector._domainkey.yourdomain.com. The selector is chosen by your email provider:
| Provider | Usual DKIM selector |
|---|---|
| Google Workspace | |
| Microsoft 365 | selector1, selector2 |
| Mailchimp | k1, k2, k3 |
| SendGrid | s1, s2 |
| Proton Mail | protonmail, protonmail2, protonmail3 |
| Fastmail | fm1, fm2, fm3 |
To find the exact selector, open any email you sent, view the original message or headers, and look for s= in the DKIM-Signature line. Use 2048-bit keys where possible; keys under 1024 bits are rejected by many receivers.
Gmail, Yahoo and Outlook Sender Requirements
Since 2024, Gmail and Yahoo require every sender to have SPF or DKIM. Bulk senders (around 5,000+ emails a day) must have SPF, DKIM and DMARC (at least p=none), aligned with the From domain, plus one-click unsubscribe. Microsoft applies similar rules to Outlook.com. If your records fail here, expect more emails to land in spam.
Changed a record? It can take time to update everywhere. Watch it go live with our DNS Propagation Checker, and check who manages your domain’s DNS with the Whois Domain Lookup.
FAQs
How do I check my MX records?
Enter your domain in this MX Lookup and click Check Records. The tool lists every MX record with its priority, the mail server’s IP address and your detected email provider.
What does MX priority mean?
Priority decides the order mail servers are tried. The lowest number is used first; servers with higher numbers are backups used only if the first one is unavailable.
What is the SPF 10 lookup limit?
SPF may use at most 10 DNS lookups, counting every include, a, mx, exists and redirect, including nested ones. Going over the limit makes SPF fail with a PermError for all your email.
Can I have two SPF records?
No. A domain must have exactly one SPF record. If you use several services, combine them into one record with multiple include: entries.
What DMARC policy should I use?
Start with p=none and a rua report address, fix any legitimate senders that fail, then move to p=quarantine and finally p=reject for full protection against spoofing.
How do I find my DKIM selector?
Open an email you sent, view its headers and find the DKIM-Signature line. The value after s= is your selector. Enter it in the optional field to check that key.
Why are my emails going to spam?
Common reasons are a missing or failing SPF record, no DKIM signature, no DMARC record, a blacklisted sending IP, or spammy content. Fix any Problem or Warning shown by this tool first.
Is this MX and SPF checker free?
Yes. It is free with no signup, within a fair-use limit of a few checks per minute.
