Yes, this HOWTO is still being maintained. In the past, Ambrose was guilty of being too busy working on two jobs and didn't have much time to work on this, my apologies. As of v1.50, David Ranch revamped the document and got it current again.
If you think of a topic that could be included in the HOWTO, please send email email@example.com. It will be even better if you can provide that information. We will then include the information into the HOWTO once it is both found appropriate and tested. Many thanks for your contributions!
We have a lot of new ideas and plans for improving the HOWTO, such as case studies that will cover different network setup involving IP Masquerade, more on security via strong IPFWADM/IPCHAINS firewall rulesets, IPCHAINS usage, more FAQ entries, etc. If you think you can help, please do! Thanks.