Novices to the network world should check out the educational animated movie at the Warriors of the Net site. The Computer Networking section of WebJunction has many resources dedicated to understanding computer networks in libraries.
Along with TCP/IP, Ethernet is the dominant technology in wired local area networks (LANs). Lantronix has a good Ethernet Tutorial, though the third part of it includes too many sales pitches. This tutorial has some information about the different types of cables commonly used in local area networks, but for more in-depth information, see Ethernet Cable Identification and this FAQ on CAT-5, CAT-6 and other cabling standards.
If you’re interested in TCP/IP, the Learn Networking site has an introduction, and they also have a tutorial about subnetting. You can calculate subnets by hand, but a lot of administrators just use a calculator. Microsoft also has some information about IP addressing. If you need to do some basic connection troubleshooting, TCP/IP Troubleshooting at the Microsoft site will teach you to use some basic tools such as ping and ipconfig.
For more information about wireless networking, see Recipes for a 5-Star Library.
The FCC’s article, What is Broadband? defines broadband and discusses its importance and the different types. Our article on Internet Access and ISPs also has information on this subject.
The SANS Institute creates an annual list of the Top 20 Security Risks. While this list may go beyond the scope of the small to medium-sized library, it represents the most accurate compilation of malicious activity on the Internet. Microsoft’s Security Guide for Small Business provides an excellent overview of establishing a secure network.
Microsoft Visio is often used for network diagrams, and libraries can buy it at a discount from TechSoup. Gliffy is an easy-to-use online program with a free and a paid version. Dia and Networknotepad are two free, open-source diagramming programs. Also, most network monitoring programs can automatically create a map of your local area network and/or your wide area network.
Common threats: Infopeople describes Common Security Threats and Vulnerabilities. Microsoft has similar information on pages 5 to 9 of their Security Guide for Small Business. While written a few years ago, Why You Need a Firewall by Cisco also identifies the different types of attacks that are prevalent on the Internet.
Vulnerability Scanning Tools: Nmap is another popular, free tool which scans your network and looks for vulnerabilities. By default it runs from the command line, but you can also find several free graphical interfaces (e.g., Zenmap for Linux and NmapView for Windows). For a short beginner’s guide, see Nmap for Beginners. For a thorough run-down, see Secrets of Network Cartography. Also check out this list of Top 10 Vulnerability Scanners as voted on by security experts. Most of the tools on this list are commercial, and some are quite expensive.
Security Policies 101 highlights several reasons for implementing security policies and also illustrates the difference between technical and administrative policies.
Non-technical Hurdles to Implementing Effective Security Policies by Gary Kessler provides an important non-technical perspective on security policies.
Search Security’s Firewall Architecture Tutorial tells you how to choose firewalls and where to place them on your network. Windows Networking also has an article on Choosing a Firewall. It’s a few years old now but still has relevant advice. A Guide to Unified Threat Management has advice on researching and testing these devices. A Unified Threat Management (UTM) system is a hardware appliance that has firewall capabilities as well other security features (e.g. spam filtering, antivirus filtering, and intrusion detection functionality). Network World’s Firewall Buyer’s Guide is a good resource for comparing specifications, but since it relies on manufacturers to submit information, there are currently no Cisco products listed.
Connectivity Troubleshooting from WebJunction and How to Troubleshoot TCP/IP in Windows XP both explain ping, traceroute and other basic troubleshooting tools. A Survey of Network Monitoring Tools from WebJunction and ABC: An Introduction to Network Monitoring from CIO.com both explain the different functions performed by this type of tool. Stanford Linear Accelerator Center has an exhaustive list of free and commercial solutions.
For advice from the library community, see this thread on Bandwidth Limiting (aka traffic shaping) at WebJunction.
The QoS article on the Gentoo Wiki server tells you how to build your own packet shaper using open-source software, but it also explains the concepts that underlie packet shaping and Quality of Service.
The Options for Network Optimization gives a quick overview of the various techniques used to speed up a WAN link or an Internet connection. WAN Optimization Appliances at the Network Computing site offers a review of four popular optimization tools.