DIY ISPs of the world, unite!
When you're an ISP offering access to the Internet, you need to keep track of a number of things.
Don't forget that subscribers may wish to view/change information themselves (bandwidth graph, DNS delegation, etc).
For all these tasks, you need some kind of software.
This is the process of assigning configuration to the end-user equipment (CPE). This includes IPv4 and IPv6 ranges, DNS servers, NTP servers, and so on.