Even with the best protection, no computer network is entirely safe from attacks. However, by taking prudent approaches with technology and company policies, you can protect against most attacks.

Ten Tips to Fight Viruses 1. Use anti-virus software and firewalls. 2. Routinely update virus protection technology. 3. Block executable attachments at the firewall. 4. Don't access executable files. 5. Block access to hacker Web sites. 6. Regularly change passwords. 7. Authenticate questionable e-mails. 8. Don't respond to e-mail from questionable sources. 9. If infected, ensure that all computers and removable media are cleaned of virus. 10. Stay vigilant.

Today's virus technology ranges from commonly available virus protection software to firewalls that limit what comes into and goes out of the computer. The more critical the system, the more protection it should have. Some financial institutions, for example, have commercial strength virus protection systems, around the clock monitoring and multiple firewalls. A system that doesn't go online can probably get by with simple anti-virus software to prevent viruses contained on floppy disks or CDs.

Multiple firewalls and anti-virus software programs can help eliminate viruses because one may catch what the other doesn't.

While it costs money to stay vigilant, it costs even more to ignore the threat and deal with the aftermath of a hacker attack. A virus can disrupt a business from several hours to several days. It can cost a fortune to hire specialists to fix the problem, not to mention the losses that can be suffered in sales and production.

Anti-virus software providers routinely provide patches to handle the newest attacks. However, users needs to make sure they install the patches when they become available. It's a good idea to check for software updates one or more times a week and check for updates anytime you learn of a new virus. Similarly, firewalls need to be updated on a regular basis.

Even if a virus passes through a firewall, you can thwart many computer attacks by knowing which files are generally safe to open and which should be deleted immediately. Here are some other virus recommendations:

 Don't click on executable attachments. Such attachments are the favored virus delivery method of many hackers. An executable attachment is a file with a name ending in ".exe." It is really a program that, when opened, causes the operating system to run a program.

 Block internal users from going to pornographic and hacking-related Web sites. Simply visiting these sites can infect the viewing computer with a hard-to-detect "Trojan Horse" virus. Such a virus sits inside of what appears to be safe material and attacks a system later.

 Use hard-to-guess complex passwords for internal network resources and local computer accounts, as well as network user accounts. Many computer attacks come from internal sources who figure out passwords.

 If an e-mail is in doubt, make sure the request is authentic by contacting the sender directly by phone or via an e-mail address known to be authentic.

 Don't respond to questionable e-mails. A hacker often sends initial e-mails just to see if online addresses are valid. By responding, you validate the address.

 Back up your systems and have a recovery plan in place if one or more of your computers succumbs to a virus. In that event, make sure you delete not only any e-mail that might have transmitted the virus, but also any attachments from a "temp" folder, "recycle bin" or "waste basket." You should also change passwords because some viruses record keystrokes. Inspect all disks to make sure they are virus-free.