Email Blacklist (DNSBL)
Checks whether an IP address (or a domain's IPs) is listed on public email blacklists such as Spamhaus, SpamCop, and Barracuda. Essential for diagnosing why your emails are bouncing or landing in spam folders.
Frequently asked questions
- Why is my mail server on a blacklist?
- Usually: a compromised account sent spam, your server has a weak password, or a shared IP (VPS) was used by a prior tenant for spam. Some blacklists are automated; others require manual review.
- How do I get delisted?
- Fix the cause first (close the relay, rotate passwords, secure forms). Then visit the blacklist's site — Spamhaus, SpamCop, Barracuda each have delisting portals. Review typically takes 1–72 hours.
- Which blacklists matter most?
- Spamhaus SBL/XBL is used by about 70% of major receivers (Gmail, Outlook, Apple). SpamCop is second. Being on just one can block your mail; being on multiple usually means your server is compromised.