Problem with using $GENERATE for reverse-lookup (PTRs)

[D. J. Bernstein]

> In particular, I want to ensure
> reverse-lookup for all IPs in say, 172.16.1.0/24 resolve to something
> like "host-172-16-1-?.example.com".

That's a reverse DNS wall. The easy way to set it up is to delegate the
in-addr.arpa domains to walldns, part of the djbdns package:

   http://cr.yp.to/djbdns/faq/walldns.html

---Dan