Blacklist Check

A DNSBL is a published list of IP addresses known for sending spam. Mail servers query these lists to decide whether to accept mail from a given IP.

Common causes are a compromised account sending spam, a misconfigured server acting as an open relay, or inheriting a "dirty" IP from a previous user. Each list has its own delisting process.

Fix the underlying issue (secure accounts, close open relays), then use the specific blacklist's removal request page. Listing this tool provides the source list for each hit.