Hooking up a small LAN of UNIX machines is easy. It simply requires an Ethernet controller in each machine and the appropriate Ethernet cables and other hardware. Or, if your business or university provides access to the Internet, you can easily add your Linux machine to this network.
The current implementation of TCP/IP and related protocols for Linux is called ``NET-2''. This has no relationship to the so-called NET-2 release of BSD UNIX; instead, ``NET-2'' in this context means the second implementation of TCP/IP for Linux.
Linux NET-2 also supports SLIP---Serial Line Internet Protocol. SLIP allows you to have dialup Internet access using a modem. If your business or university provides SLIP access, you can dial in to the SLIP server and put your machine on the Internet over the phone line. Alternately, if your Linux machine also has Ethernet access to the Internet, you can set up your Linux box as a SLIP server.
For complete information on setting up TCP/IP under Linux, we encourage you to read the Linux NET-2 HOWTO, available via anonymous FTP from sunsite.unc.edu. The NET-2 HOWTO is a complete guide to configuring TCP/IP, including Ethernet and SLIP connections, under Linux. The Linux Ethernet HOWTO is a related document that describes configuration of various Ethernet card drivers for Linux. The Linux Network Administrator's Guide, from the Linux Documentation Project, is also available. See Appendix A for more information on these documents.
Also of interest is the book TCP/IP Network Administration, by Craig Hunt. It contains complete information on using and configuring TCP/IP on UNIX systems.