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Chapter 11:
Securing Your Network
(You can set up most server-based antivirus software to update its list of known viruses
securely over an Internet connection automatically.) Also, because e-mail is the chief
mechanism of transmission for computer viruses these days, make especially sure
that you run antivirus software on your e-mail server. I recommend updating virus
signatures on an e-mail server hourly, if possible. This is because new e-mailborne
viruses can spread throughout the world very rapidly--in a matter of hours. By having
your antivirus software on your e-mail server update itself hourly, you're a little more
likely to get a necessary update before the virus hits your network.
TIP
Consider using antivirus software from different companies for differents parts of your
network. For example, you might use one company's antivirus software for your e-mail server and
some other company's software for your other computers. While rare, I have seen cases where one
company's offerings do not detect certain viruses, while a different company's offering does. On a
network that I manage, we run one company's antivirus software on all the desktop computers and
a different company's antivirus software on the e-mail server. I've seen cases where one of those
systems permits a virus that the other one catches.
You should also run antivirus software on your workstations, but you shouldn't
rely on this software as your primary means of prevention. Consider desktop antivirus
software as a supplement to your server-based software.
Chapter Summary
In this chapter, you learned about common security threats and read advice that can
help you formulate and implement good security practices. You should seriously
consider retaining an outside security consultant to help you set up your security plans
and to review and audit them on a regular basis.
Even in an entire book devoted to the subject of network security, you can't
learn all you need to know to make a network as secure as possible. New threats are
discovered constantly, and the changing software landscape makes such information
quickly obsolete. If you're responsible for network security, you should know it's a job
that never sleeps, and you can never know enough about it. You need to spend time
learning more of the ins and outs of network security, particularly for the operating
systems that you use on your network. The following books can help further your
network security education:
Network Security: A Beginner's Guide, Second Edition, by Eric Maiwald
(McGraw-Hill/Professional, 2003)
Hacking Exposed: Network Security Secrets and Solutions, Sixth Edition, by Stuart
McClure, Joel Scambray, and George Kurtz (McGraw-Hill/Professional, 2009)
Windows 2000 Security Handbook, by Tom Sheldon and Phil Cox (McGraw-Hill/
Professional, 2001)