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Top 10 network security tips

Strengthen your organization's network security with these best practices.

I was asked by a client to develop a "best practices" guide for securing Microsoft IIS 5.0. In my search for supporting reference material, I came across a very informative document called The 60 Minute Network Security Guide on the National Security Agency Web site ( The document is only about 40 pages long, but it's packed with valuable pearls of wisdom on how to secure your network enterprise, including specific information for Windows and Unix systems. The document is what is known as a "best practices" guideline for network security. Here's a summary:

  1. Make sure you have a security policy in place -— The security policy is the formal statement of rules on how security will be implemented in your organization. A security policy should define the level of security and the roles and responsibilities of users, administrators and managers.
  2. Make sure all of your operating systems and applications are patched with the latest service packs and hotfixes -— Keeping your systems patched will close vulnerabilities that can be exploited by hackers.
  3. Keep an inventory of your network devices -— Develop and maintain a list of all hardware/software components, and understand which default software installations provide weak security configurations.
  4. Scan TCP/UDP services -— Turn off or remove unnecessary services. Unneeded services can be the entry point attackers use to gain control of your system.
  5. Establish a strong password policy -— Weak passwords could mean a compromised user account.
  6. Don't trust code from non-trusted sources.
  7. Block certain e-mail attachment types -— This list includes .bas, .bat, .exe and .vbs.
  8. Don't provide more rights to system resources than necessary -— Implement the concept of "least privilege".
  9. Perform your own network security testing -— Find the holes before the attackers do!
  10. Implement "defense-in-depth" -— Don't rely on just one control or system to provide all the security you need.

I recommend downloading this document and reading it from cover to cover. It's packed with excellent tips and techniques to help secure your network environment.

About the author:
Mark Edmead, CISSP, SSCP, TICSA, is president of MTE Software, Inc. (, and has more than 25 years' experience in software development, product development and network systems security.

This was last published in November 2002

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