It's a patch to djbdns to allow dnscache to perform resolution or forwarding according to the query zone.
The latest version is djbdns-1.04-fwdzone. It works with djbdns-1.05 too.
The FORWARDONLY environment variable has been disabled. By default, dnscache only performs iterative queries, like in pre-1.03 versions.
To configure the root/servers directory of dnscache :
If my.zone has the sticky bit set, dnscache will perform recursive queries for the zone : my.zone must contain a list of DNS caches to whom dnscache will forward the queries.
If my.zone has the sticky bit cleared, dnscache will perform iterative queries for the zone : my.zone must contains a list of appropriate DNS servers.
If @ has the sticky bit set, dnscache will forward any queries it cannot find a preconfigured zone for. This is most useful behind a firewall with a split-DNS configuration.