Ultra-minimal authoritative DNS server, Dyndns replacement
By default, nanodns reads data from /var/lib/nanodns/. For every domain, put a file into this directory which has the FQDN as filename (e.g. 'foo.bar.baz.org.', note the final dot) and contains the IPv4 address of the host. Make sure the files are world-readable, as nanodns drops all privileges and changes its UID/GID to "nobody".
Also included is an example PHP script to quickly update these files from the Web. Some inspiration taken from http://smorgasbord.gavagai.nl/2011/08/homemade-dynamic-dns-service/