2. What are the IP addresses?
The IP address is an only identifier that is applied to each device connected to an IP network. This way, different elements taking part in the network (servers, routers, user computers, etc) communicate among them using their IP address as identifier.
In version 4 of the IP protocol (used nowadays) addresses consist of 4 numbers of 8 bits (an 8 bits number take a value from 0-255 range) that they use to be represented separated by points, for example: 155.54.210.63
A version 4 IP address has 32 bits, which is equivalent to 232 different IP addresses (4 billions more or less).