"Yes, The Book of PF, 4th Edition Is Coming Soon" https://nxdomain.no/~peter/yes_the_book_of_pf_4th_ed_is_coming.html (also https://bsdly.blogspot.com/2025/07/yes-book-of-pf-4th-edition-is-coming.html), title still true, actual publication date TBD, #bookofpf #pf #packetfilter #openbsd #freebsd #networking #security #trickery #hacking