Like most interesting things you can do with a computer, attaching it to a network involves some specialized hardware. You'll need a NIC (Network Interface Card) to connect to a LAN, perhaps a modem to connect to an Internet provider, or perhaps both (or several of each, or none).
For the purposes of configuration, we can divide said hardware into PCMCIA (for laptops) and non-PCMCIA categories. The reason for this somewhat lopsided division is that currently PCMCIA hardware is not supported by the kernel distribution, but by a separate package which includes the necessary drivers (as kernel modules) and some software for configuration and management of PCMCIA devices. Everything else, of course, is handled by the standard kernel distribution.
The drivers for network devices that the kernel supports are included in the netmods package (slakware/n3/netmods.tgz). If you haven't installed netmods yet, you'll need to do so now. (See Chapter 16 for help with installing packages.)
Kernel modules that are to be loaded on boot-up are loaded from the rc.modules file in /etc/rc.d. The default rc.modules file includes a “Network device support” section. If you open rc.modules and look for that section, you'll notice that it first checks for an executable rc.netdevice file in /etc/rc.d; rc.netdevice is created if setup successfully autoprobes for your network device during installation. If it did, you're probably not reading this (ooh, paradox); if it didn't, read on.
Below that “if” block is a list of network devices and modprobe lines, each commented out. Find your device and uncomment the corresponding modprobe line, then save the file. Running rc.modules as root should now load your network device driver (as well as any other modules that are listed and uncommented). Note that some modules (such as the ne2000 driver) require parameters; make sure you select the correct line.
PCMCIA network devices should be even easier than others. Make sure you have the pcmcia package (slakware/a11/pcmcia.tgz) installed. (see Chapter 16 for details on package installation.) Upon installation, the pcmcia package will create an rc.pcmcia file in /etc/rc.d and an /etc/pcmcia directory, and will install drivers to /lib/modules/<kernel version>/pcmcia. The cool thing about the pcmcia package is that it will attempt to autodetect the insertion and removal of supported pcmcia devices; you should be able to simply insert your pcmcia network adapter and listen for the beep it gives when loading the necessary modules. If you remove the card, its driver modules should be automatically removed.
Unfortunately, if you compile a newer kernel version you will probably have to recompile pcmcia-cs to get the drivers updated. Of course, the source is included; check the source/a/pcmcia directory for source, scripts, and any documentation we have to help you with that.