This varies by operating system. There is a program that works on many Unices (though not Linux or Solaris), called netconfig, that allows one to do this and documents many of the variables. It is available by anonymous FTP from . In addition, Richard Stevens’ TCP/IP Illustrated, Volume 1 includes a good discussion of setting the most useful variables on many platforms. • Are there object-oriented network programming tools? Yes. One such system is the ADAPTIVE Communication Environment (ACE). The README file for ACE is available on the Web at . All software and documentation is available via both anonymous ftp and the Web. ACE is available for anonymous ftp from . That’s a compressed tar archive approximately 500KB in size. This release contains contains the source code, documentation, and example test drivers for C++ wrapper libraries.