Krein's checklist for security layers includes: a network firewall and good antivirus/anti-malware software, kept up-to-date.
He also recommends that those who have several computers in the home put a personal firewall on any laptop they are using to further protect it from infections that may have gotten into other computers in the home network. If your laptop has Windows XP, it comes with a personal firewall; all you have to do is enable it. Windows Vista has a firewall that is turned on by default. But if you're not working with a system that already has a personal firewall, software is available from most major security-software vendors.
3. Forgetting Wi-Fi security
How many wireless networks can you log onto at home? Can you see your neighbor's network? Sure, you only log into your own. But can you trust everyone to be so ethical? How easily could someone get onto your network and see sensitive information?
Krein advises that home networks have some kind of encryption, such as Wi-Fi Protected Access, or the newer standard of encryption known as WPA2, enabled. It is important, said Krein, to ensure your wireless router is enabled and configured for encryption and that all wireless network devices are configured properly so the security will work. It takes some time, he said, but it is well worth it.
Most newer Wi-Fi-certified devices support WPA protocol; it is just a matter of configuring it properly to work, which is information you can probably get simply from the owner's manual of your wireless router. But if you are using an older device, you may need to upgrade.
Also see Wireless Security: The Basics
4. Failing to separate your business from your home
While it may not be necessary in all instances of home office scenarios, Krein recommends considering the nature of your work when deciding whether or not you need to segregate your work network from your home network. Certain types of work are subject to various laws and regulations. Using the same computer for work as you do for personal business could present an ethical, or even legal, issue."
"If you are doing work that requires PCI compliance, such as working with credit card numbers, or if its medical work and you are bound by HIPAA rules, you would want to segregate your networks."