Email / IP Blacklist Checker

Why blacklist checks matter

If your mail server's IP address is on a major DNSBL (DNS-based blackhole list), your outbound mail starts getting silently rejected or junked. Gmail, Outlook and most corporate mail systems consult these lists in real time when deciding whether to accept a message.

How an IP ends up on a blacklist

• Compromised account on the server sent spam.
• Mailing-list with unconfirmed subscriptions hitting spam-trap addresses.
• Missing SPF / DKIM / DMARC records.
• Shared hosting where another tenant misbehaved (less common — most hosts segregate outbound IPs).
• Dynamic / residential IP range used for outbound mail.

If you're listed

1. Fix the underlying cause — secure compromised accounts, add SPF/DKIM/DMARC.
2. Submit a delisting request to each blacklist (most have a self-service form).
3. Monitor for re-listing for the next 30 days.

Hostiko monitors all our outbound mail IPs continuously and proactively delists if any blacklist incident occurs.