- Home
- Cyber Security
- Blacklist Checker
Free tool · DNS blocklists
Blacklist Checker
Check if an IP address or your mail server is on an email blocklist (DNSBL), with reverse DNS checks and links to request removal.
- 10 major blocklists
- Reverse DNS check
- Your IP shown on top
Nothing you enter is stored, and your IP address is only shown to you. Checks are DNS lookups against each blocklist; we never contact the IP itself.
How it works
Why email ends up blocked
Mail servers check the sending IP against public blocklists. If your server or Microsoft 365 tenant IP is listed, your email can bounce or land in spam until it's removed.
Checks
Checks
Checks
Best practice, your way
Free tools. Expert help when you want it.
Getting listed usually means something is wrong: a hacked account, an infected PC or a misconfigured server. Our specialists find the cause, fix it and get you delisted.
Free tools
Do it yourself, anytime
Includes
- Blacklist checker for any IPv4
- Open port check
- Email Security Checker with PDF report
Easy to miss on your own
- Hacked mailboxes sending spam overnight
- Listings you only learn about from bounces
- Asking for removal before fixing the cause
Blocklist Removal
Done for you, quickly
Everything in Free, plus
- Find out why you were listed
- Clean up the account, PC or server
- Removal requests to each list
- Steps to stop it happening again
Handled for you
- Root cause found and fixed
- Removal requests sent for you
- Clean-up checked before we close it
Managed Email Security
Looked after, month to month
Everything in Removal, plus
- SPF, DKIM and DMARC kept correct
- Mailbox and sign-in monitoring
- Fast response if you're listed
- Monthly plain-English report
Peace of mind
- Mail flow and bounces watched
- Hacked mailboxes caught early
- One team to call when email bounces
Keep going