Blacklist Checker

Email blacklists (also called DNS-based blacklists or DNSBLs) are databases of IP addresses and domains that have been identified as sources of spam. Email servers check these lists in real-time when deciding whether to accept an incoming email.

Being listed on a major blacklist like Spamhaus or Barracuda can cause your emails to be rejected or sent to spam across millions of inboxes. The impact varies by blacklist — Spamhaus is used by the majority of email providers, while smaller lists may have limited impact.

Common causes of blacklisting

• Sending to purchased or scraped email lists with high bounce rates
• Hitting spam traps (recycled or pristine honeypot addresses)
• Compromised accounts or servers sending spam without your knowledge
• Shared IP addresses where another sender on the same IP was blacklisted