Whereas SOCKS attempts to provide a single, general proxy, TIS FWTK provides individual proxies for the most common Internet services (as shown in Figure 9-5). The idea is that by using small separate programs with a common configuration file, it can provide intelligent proxies that are provably safe, while still allowing central control. The result is an extremely flexible toolkit and a rather large configuration file.
Using proxy-aware user procedures is the most common configuration for TIS FWTK. The support for proxy-aware client programs is somewhat half-hearted (for example, no proxy-aware clients or libraries are provided). Because it's a dedicated FTP proxy, it provides logging, denial, and extra user authentication of particular FTP commands.
x-gw is an X gateway. It provides some minimal security by requiring confirmation from the user before allowing a remote X client to connect. The X gateway is started up by connecting to the Telnet or rlogin proxy and typing "x", which displays a control window.