ldap2dns converts an LDAP DNS database to a tinydns data file. tinyadmin is a graphical interface to the LDAP DNS database used by ldap2dns.
mkdns converts a MySQL DNS database to a tinydns data file. It lets authorized browsers edit the MySQL DNS database.
sql2tinydns is similar to mkdns.
dhcp_dns watches dhcpd for new DHCP address assignments, and publishes those addresses through tinydns.
tinydyndns publishes dynamic IP addresses authenticated through POP connections.
MyDNS publishes DNS information from a MySQL database.
Posadis publishes DNS information from BIND-style zone files. Security history: Buffer overflow, allowing attackers around the Internet to take control of the server; fixed in m5pre2 (2002.03.30). Someone announced an exploitable buffer overflow in m5pre2 a few weeks later; the history here isn't clear from the Posadis web pages.
NSD publishes DNS information from BIND-style zone files. Security history: Unclear. The NSD documentation includes bugs like ``Very strange coredump in hash_destroy() that happens sometimes'' without any analysis of their security impact. Is that an exploitable buffer overflow?
PowerDNS publishes DNS information from MySQL databases, PostgreSQL databases, Oracle databases, IBM databases, LDAP databases, or BIND-style zone files. Security history: Unclear, like the NSD security history.
MaraDNS is a general-purpose DNS server.
lbnamed is a load-balancing DNS server.
lbdns is another load-balancing DNS server.
Oak DNS Server is a good example of why novices shouldn't try to write DNS software. The digitallumber.net domain, served by Oak DNS Server 1.0, is inaccessible to a huge number of clients that try AAAA lookups before A lookups: the server incorrectly returns NXDOMAIN for AAAA, effectively wiping out its own A record.
MaraDNS can act as a cache.
I don't know why anyone would want to use these caches in place of dnscache.
ares is a DNS client library.
perldns is a DNS client library for Perl.