Check whether an IP or domain is listed on major email/spam blacklists
Blacklists (DNSBLs) are shared lists that mail servers and spam filters consult to decide whether to trust traffic from an IP address. Getting listed on one can seriously affect email deliverability and, in some cases, general trust in a domain. This tool checks an IP (or a domain's resolved IP) against four real, widely used lists: Spamhaus ZEN, SpamCop, Barracuda, and SORBS.
How to use:
Tips: if you manage a mail server and see a "LISTED" result, most blacklists publish a delisting process on their own site, search the list's name plus "delist" to find it.
It means that particular blacklist has flagged the IP, usually due to observed spam, abuse, or being part of a range known for such activity, mail servers that consult that list may reject or flag mail from it.
Checking a domain resolves it to its current A record IP first, useful when you know the domain sending mail but not its mail server's IP offhand.
Each blacklist publishes its own delisting process, usually on its own website, search for the list's name plus "delist" or "removal" to find the correct steps.
No, these four lists are widely used but not exhaustive, and deliverability also depends on factors like SPF/DKIM/DMARC setup and sending reputation elsewhere.