What is an ogre like?
An onion.

What is computer and network security  like?
An ogre! The best computer and network security is layered. 

Why? Because there are hundreds of attack vectors against technologies and people. 

So, what should the layers be? Following are a few that you REALLY REALLY should have:

1) Anti-virus software on your computer (with anti-spyware/anti-phishing)
2) A software firewall on your computer
3) A fully updated and patched computer
4) An up-to-date physical firewall/router
5) Anti-virus software on your email server
6) Anti-spam software on your email server
7) A fully updated and patched server
8) Great backups for all computers and servers

Here is what would be ideal to have:

1) A firewall that is a full unified threat management (UTM) device. That is, it's a firewall but also acts as an Intrusion Prevention System (IPS). It scans for viruses, scans for spyware, scans for certain types of content, and it can scan for certain application signatures. This takes your security to the next level.

2) A filtering service for email traffic, i.e. something that scans your email for viruses, phishing attempts, and of course, SPAM. Why have this again? Because it will use a different engine than the two above, which gives you MUCH more coverage. It also takes the load off your server, so it is faster.

3) A web proxy that allows you to monitor your network traffic. That way, if someone gets a virus you can find them quickly. You can also prevent critical corporate data from leaving your network to parts unknown. 

4) A disaster recovery plan in the event that there is a breach.

5) A great IT company to help pull it all together (of course!).

Again, security is about layers. The more you have, the less likely you are to be attacked because hackers will usually move on to easier targets if they hit a wall. 

Feel free to contact me with any questions you might have.