Java™ Network Programming and Distributed Computing

1.8. Security Issues: Firewalls and Proxy Servers

Network security is an important topic, both for network administrators charged with protecting the computer systems of companies and organizations and for developers producing network software. Even if that software is fairly innocuous and not worth fitting out with sophisticated security mechanisms such as passwords and encryption, it is still important to take security issues into consideration, for the simple reason that network security restrictions on some local area networks may prevent software from working.

In an ideal world, we could implicitly trust incoming data from machines connected to the Internet, as well as the actions of colleagues sending outgoing data from within a local area ...