IP address
From AMule Project FAQ
An IP address is a unique value you are given when connecting to a net using the Internet Protocol.
Internally, IP addresses are 4 bytes numbers. Anyway, their common use is splitting this addresses into 1 byte numbers with a dot (.) between them. Since the range of values a 1 byte number can be is 0 - 255, the range of IP addresses goes from 0.0.0.0 to 255.255.255.255 which makes up to 2^(4*8) possible IP addresses.