The Internet Protocol version 4 is the currently used network protocol for transmitting data over a packet-oriented network. It was specified in RFC 791 The data to be transmitted is broken down into packets and routed over the network. Each packet can take a different route.
Source and destination and all intermediate stations to have this unique IP addresses with a width of four bytes (32 bits). The common specification is in the dot notation: a.b.c.d, where a through d are numbers between 0 and 255. This leads to a maximum number of about 4.3 billion IP addresses.
By far not every entry can also be used. There are special addresses (such as broadcast, 255.255.255.255) and private IP addresses to build local networks. In addition, the IP addresses of institutions and companies are allocated in blocks from the RIR, so that ia not every single IP address is also used.
Due to the rapid expansion of the Internet and other IP-based networks, the demand for IP addresses increased to such an extent, that it is expected that around 2012, all IPv4 addresses are exhausted.
Therefore, a successor standard IPv6 (Internet Protocol version 6) was created, which brings a much larger address space and other improvements. In modern operating systems, IPv6 support is now integrated. In 2004, the first changes from IPv4 towards IPv6 began.