The main idea is that smtpctl spf walk will read a list of domains from stdin and output a list of IP addresses and ranges to stdout, allowing it to be used in scripts, to generate file lists, or to be piped directly into pfctl to feed a table.
The title of this post should be "Spam Filtering on OpenSMTPD", but i didn't want to define the my home page with that word. Running an e-mail server is a challanging and low-reward task, so we need to keep this as simple as we possibly can. This is I classify mail using SpamAssasin these days.
Bitmessage is a P2P communications protocol used to send encrypted messages to another person or to many subscribers. It is decentralized and trustless, meaning that you need-not inherently trust any entities like root certificate authorities. It uses strong authentication which means that the sender of a message cannot be spoofed, and it aims to hide "non-content" data, like the sender and receiver of messages, from passive eavesdroppers like those running warrantless wiretapping programs.