not intended to be a full answer, but maybe help you search the existing documentation a bit easier..
hostname: the name of a computer on the network (usually yours)..
domain: linuxquestions.org would be the domain of the system running this message board.
bootp: an older, simpler version of DHCP.. it is a way for computers to automatically get their IP address and other information when they boot up.. (instead of you having to enter them in as a "static" address).
gateway: the computer or IP address that connects you to the rest of the internet (or whatever network you are attached to)
netmask: 255.255.255.0 is a netmask. If you have this netmask, it means that your computer considers all addresses that have the same first three sets of digits of the IP address as the computer's IP address to be on the same subnet and require no routing. A subnet of 255.255.0.0 would consider everything that has the same first two sets of digits to be on the same subnet.
You really ought to read the networking howto on
www.linuxdoc.org my off-the-cuff explanations are bound to have errors and unclear descriptions..