Server Essentials

Networking Essentials?

Features of networks: topologies, peer-to-peer, client server, network access methods

Services: communication, file transfer, online databases

Protocols: purpose of protocols, an example of the function of protocols.

Data Security Issues: access control, virus protection, backup, hacking, firewalls.

Browse those topics on the wiki. Here's a couple links to get you started:

http://en.wikipedia.org/wiki/Computer_networking

http://en.wikipedia.org/wiki/Computer_network