Email Blacklist (DNSBL) Checker
Is your mail server IP or domain on a spam blacklist? We check it against 24 DNSBLs at once — so you know why your email is bouncing or going to spam.
Why does being blacklisted matter?
A DNSBL (DNS-based blocklist, also called an RBL) is a list of IP addresses known for sending spam. Mail servers query these lists in real time and reject or junk mail from listed IPs. If your sending IP is listed, legitimate email bounces or lands in spam.
If you're listed: find out why on the blocklist's site (compromised server, open relay, a spammy neighbour on a shared IP, or a poor sending reputation), fix the root cause, then request delisting through that list's removal form. Most lists de-list automatically once the bad behaviour stops. Keep your SPF, DKIM and DMARC correct to protect your reputation — check them with our Email Deliverability Checker.
Note: a few lists (e.g. Spamhaus) block queries from shared/public resolvers and may show as “couldn't query” here; check those directly on their site. DNSBLs are IPv4-only.