S5H

S5H is a honeypot-based blacklist. The operators deploy multiple servers that masquerade as mail servers across the internet. Since these honeypots never receive legitimate email, any IP that attempts to send mail to them is considered a spam source.

The honeypots log every IP that attempts to connect and send email. These IPs are automatically added to the blacklist. Since the honeypot addresses are never published and never registered for any service, no legitimate mail server should be sending to them.

S5H doesn't have a public self-service removal page. If you believe your listing is a false positive (for example, your IP was reassigned from a previously listed user), try contacting the administrators through their website.