8.5. NETWORK CONFIGURATION WITH SYSTEMCONFIGURATION

When an application communicates with network services, having an accurate view of the network is important. Should the application fail to notice a change in its environment, it could stop talking to the computer at the remote end of the connection (an availability risk) or even start sending to and receiving from a different machine (affecting the integrity and confidentiality of the network traffic).

Mac OS X's networking features are based on UNIX's connection capabilities, which were designed at a time when computers were installed in a single location and connected to a relatively static network. The original Macintosh, in the speech it made with a synthesized voice at its 1984 introduction, (http://www.youtube.com/watch?v=G0FtgZNOD44) said, "Never trust a computer you can't lift," but you can trust it on one thing: it isn't likely to move very far." Therefore UNIX's network software was designed to work with unchanging environments — a computer always had the same address, as would all the other computers it needed to communicate with. Furthermore, as all the other computers were run by military or academic establishments, the other machines out there could be trusted.