DynDns
A popular dynamic DNS hosting service.
Most domestic internet connections have a dynamic IP address. This is bad for Freenet, because it doesn't know where the node is when its IP changes, but it is especially bad if the Freenet node is behind a NAT firewall/router. Dyndns.org and other such services solve this problem by providing a permanent domain name for the user, which can then be inserted into node.ipAddressOverride in the freenet.ini.