The Ethernet-Howto contains detailed information on the current level of support for most of the common ethernet cards available. It covers common hardware configuration problems, and problems associated with choosing the right driver, and then getting that driver loaded and functional. It does not cover the next stages of setup (choosing an internet address, routing, etc). That information can be found in various other Linux documentation. In the early days of linux, the old ISA type Ethernet cards were the norm. The ISA bus had no sane or safe way for Linux to determine what cards were installed, or what settings each card was to use.