Proton Mail
Useful for encrypted email, custom-domain mail, email aliases, and privacy-focused business communication.
Explore Proton MailEmail DNS Tool
Email Deliverability Checker
Check whether your domain is ready to send and receive business email. Test MX, SPF, DKIM, DMARC and other email security records in one simple report.
Email Readiness Summary
Email health report
Enter a public domain to check MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, BIMI, and basic website context.
Port233 Toolkit
Documenting email security work?
Use Cyber Essentials and the IT Consultant Bundle Pack to record MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, provider details, and client handover notes.
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Useful external services
Recommended external tools
If your email DNS needs changes, you may need a reliable email host, DNS provider, or privacy-focused business suite to manage the wider setup.
Proton for Business
Useful for privacy-focused business email, VPN, password management, secure storage, and team controls.
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Email deliverability records explained
MX
MX records tell other mail servers where to deliver messages for your domain. They are the first sign that a domain can receive business email.
SPF
SPF lists the services allowed to send mail for your domain. A single, well-scoped SPF record helps reduce spoofing and delivery failures.
DKIM
DKIM signs outgoing mail with a domain key. The checker tests common selectors and any selectors you enter for the domain.
DMARC
DMARC connects SPF and DKIM results to a policy. Monitoring can start with p=none, then move to quarantine or reject after legitimate senders pass.
MTA-STS and TLS-RPT
These records strengthen encrypted mail transport and reporting. They are useful security upgrades after the core mail records are healthy.
BIMI
BIMI can publish a brand logo for supported inboxes. It normally depends on strong DMARC enforcement and brand validation.
Email deliverability FAQ
What does an email deliverability checker test?
It checks the DNS records that affect business email delivery and authentication, including MX, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, and BIMI.
Why do MX records matter?
MX records tell other mail servers where to deliver email for your domain. Without MX records, a domain may not be able to receive email.
What are SPF, DKIM, and DMARC?
SPF lists approved senders, DKIM signs outgoing messages, and DMARC tells receivers what to do when authentication fails.
Why might DKIM not be detected?
DKIM is selector-based. Port233 tests common selectors, but your provider may use a different selector that needs to be entered manually.
Does BIMI improve deliverability?
BIMI is an advanced brand indicator. It can help eligible brands show a logo in supported inboxes, but SPF, DKIM, and enforced DMARC should come first.
Can Port233 help fix email DNS records?
Yes. Port233 and Securewire can help configure DNS, Microsoft 365, Google Workspace, SPF, DKIM, DMARC, and related mail security records.
Need help fixing DNS or business email?
Port233 and Securewire help small businesses configure Microsoft 365, Google Workspace, DNS, SPF, DKIM, DMARC, MTA-STS, TLS-RPT, and practical email security controls.