Ipcalc takes an IPv4 address and netmask and calculates the resulting broadcast, network, Cisco wildcard mask, and host range. By giving a second netmask, you can design sub- and supernetworks. It is also intended to be a teaching tool and presents the results as easy-to-understand binary values.

Originally, ipcalc was intended for use from the shell prompt, but a CGI wrapper is provided to enable colorful HTML display through a webserver. You can find it in /usr/share/doc/ipcalc/examples directory.