Email Tools
Email diagnostics cover mail routing, SMTP behavior, sender authentication, and reputation indicators. Use this section when delivery rates drop, bounces spike, or mailbox placement changes unexpectedly.
When to use this category
- Inbound or outbound mail delays appear after DNS or provider changes.
- STARTTLS, banner, or SMTP handshake behavior is inconsistent.
- Deliverability posture needs SPF, DMARC, DKIM, DNSBL, and URIBL validation.
What you get from these pages
- Mail-path evidence that is useful for both ops and deliverability teams.
- Interpretation of SMTP and DNS auth results without vendor lock-in jargon.
- Direct next-step links for transport, reputation, and policy troubleshooting.
Operator tips
- Track policy changes with timestamps; deliverability regressions are often delayed.
- Separate transport failures from reputation failures before remediation.
- Re-test after MX, SPF, and DKIM changes once propagation completes.
Tools in this category
Frequently asked questions
Why can mail tests pass while inbox placement still drops?
Transport success does not guarantee reputation or policy alignment at recipient side.
Is STARTTLS failure always a hard outage?
Not always, but it is a security and trust signal that should be fixed quickly.
Can one DNS typo affect all mail?
Yes. SPF, MX, or DKIM mistakes can cause broad deliverability impact.
Do DNSBL results mean permanent blocking?
No. Listings can be temporary and policy-dependent across receivers.
Which check should I run first during mail incidents?
Start with mail-server test, then SMTP handshake, then auth/reputation checks.