SubNetCalc is an IPv4/IPv6 subnet address calculator. For given IPv4 or IPv6
address and netmask or prefix length, it calculates network address, broadcast
address, maximum number of hosts and host address range. The output is
colourized for better readability (e.g. network part, host part). Also, it
prints the addresses in binary format for better understandability.

Furthermore, it can identify the address type (e.g. multicast, unique local,
site local, etc.) and extract additional information from the address
(e.g. type, scope, interface ID, etc.). Finally, it can generate IPv6 unique
local prefixes.

WWW: http://www.iem.uni-due.de/~dreibh/subnetcalc/