# What is the "af"?

Several of the manual pages for the DNS tools in the djbwares toolset use the (super)domain name `af.example.` This is why.

Daniel J. Bernstein's djbdns version 1.05 was released back on 2001-02-11. Bernstein had been working on it since December 1999. It had no manual pages per se, only HTML documentation on Bernstein's own site on the WWW. These pages still exist. Compare Daniel J. Bernstein's original `tinydns-data` documentation with the `tinydns-data` manual page here, for example.

In the original documentation, IP addresses such as 1.2.3.4 were used as examples, as were domain names ending in `.af.mil`. This kind of thing was not uncommon at the turn of the 21st century. RFC 2606 had only just reserved `example.` as a top-level domain in 1999, a mere 5 months before Bernstein began; and IANA would not explicitly reserve ranges of IP addresses for use in documentation for another decade, with the release of RFC 5737 in 2010.

As of 2025, however, the use of domain names owned by the United States of America's Air Force was rather more jarring to readers than it would have been in February 2001. A lot of people had switched their documentation to the IANA reserved domain names, and things like `af.mil` were rather more prominent and unusual than they were back when Bill Clinton was president of the United States of America, Pink Floyd had toured just a handful of years prior, and The Princess Bride movie was only 12 years old.

Furthermore, CloudFlare had gone through a very public process of adopting the IP addresses 1.1.1.1 and 1.0.0.1 — for the purpose of providing open proxy DNS service, no less! — and combatting decades of people abusing such off-the-cuff IP addresses as placeholders in documentation and indeed as default configuration settings in real network devices. The continued use of 1.2.3.4 and suchlike in djbwares documentation was one more contributor to the world doing the same thing for a similar address range. (At the time of the change, various public services that looked up Autonomous Systems from IP address blocks gave a random company in China as the owner of 1.2.3.4, albeit listing hundreds of other companies and organizations who had just unilaterally purloined that IP address.)

So both the domain names and IP addresses were updated in the manual pages in 2025. Although the superdomain `af.mil.` could have been entirely replaced by `example.`, retaining the `af` retains some of the spirit of the original documentation, whilst introducing a talking point of where the "af" comes from (and why it does not mean what you think that it means, you dirty-minded people!) for future generations.