The DNS IP BLACKLIST
Christian Jung launched the inps.de DNSBL way back on December 29th, 2007.
Christian described the listing criteria as follows: “Every day thousands of spam e-mails arrive on our e-mail servers, which have to be processed by our anti-spam system. If an email is recognized as spam, the IP address of the sender is recorded in a blacklist for a certain period of time in order to enable faster email processing and reduce the system load.”
Today, May 25, 2020, he has announced that it is shutting down, due to concerns around GDPR and personal challenges brought on by the coronavirus pandemic.
He appears to be shutting it down in a graceful manner — not “listing the world” as so many blacklists do as the end. This is good to see.
Note that in addition to the DNSBL dnsbl.inps.de, this also affects the DNSWL (whitelist) found at dnswl.inps.de. Both are ceasing.
This blacklist contains IP addresses from which they have received mails, that were classified as spam. Your IP can be listed in this blacklist even if you have sent them a single SPAM message. IP addresses are kept in this list until the owner requests a removal. Email server admins can submit IPs to this blacklist via their API if they receive more than 250 SPAM messages daily.