Mastering Python Networking - Second Edition

The internet protocol

As network engineers will tell you, they live at the Internet Protocol (IP) layer, which is layer 3 on the OSI model. IP has the job of addressing and routing between end nodes, among others. The addressing of an IP is probably its most important job. The address space is divided into two parts: the network and the host portion. The subnet mask is used to indicate which portion in the network address consists of the network and which portion is the host by matching the network portion with a 1 and the host portion with a 0. Both IPv4 and, later, IPv6 expresses the address in the dotted notation, for example, 192.168.0.1. The subnet mask can either be in a dotted notation (255.255.255.0) or use a forward slash to express ...