About the Blacklist Check
This blacklist checker tests an IPv4 address against around ten well-known DNS blacklists (DNSBLs / RBLs), including Spamhaus ZEN, SpamCop, Barracuda and others. Being listed on these blacklists is one of the most common reasons legitimate email is rejected or sent to spam, so checking your sending IP is a key deliverability diagnostic.
You can enter an IP address directly, or a domain name — in which case the tool resolves its A record and checks that. Each blacklist is queried over DNS; a hit returns the listing's return code, which often encodes the reason. Pair this with the SPF, DKIM and DMARC checkers to cover the full picture of why mail may not be delivering.
How to use it
- Enter the sending IPv4 address, or a domain to check its A record.
- Submit to query around ten major DNS blacklists in parallel.
- See the overall verdict — clean, or listed on N blacklists.
- For any listing, note the return code and visit that blacklist to request delisting.
Examples
- Check your mail server's public IP before investigating a deliverability complaint.
- Verify a new VPS IP is not already blacklisted from a previous owner.
- Enter a domain to check whether the IP behind its A record is listed.
Frequently asked questions
What is a DNS blacklist (DNSBL)?
A DNSBL or RBL is a published list of IP addresses with a poor sending reputation — sources of spam, open relays or compromised hosts. Mail servers query these lists over DNS and may reject or flag mail from listed IPs.
My IP is listed — what do I do?
Visit the specific blacklist's website (for example Spamhaus) and follow its delisting process. Fix the underlying cause first, such as an open relay, a compromised account or missing rDNS, or you will be relisted.
Can I check an IPv6 address?
DNSBL coverage for IPv6 is limited and inconsistent, so this tool checks IPv4 addresses. If you enter a domain, it uses the IPv4 A record.
Why might a clean result still mean delivery problems?
Blacklists are only one factor. Authentication (SPF/DKIM/DMARC), content, rDNS and per-provider reputation all matter. Use the email tools together for a full diagnosis.