Today, almost every critical piece of business information is created, stored and/or managed with one or more IT-powered tools. But to many decision-makers, "IT security" starts and stops with the IT infrastructure, and is only marginally integrated with information security, physical security or other concerns, if it's integrated at all. How best to ensure that IT security doesn't begin and end at the corporate firewall?
The firewall is one of the best security control points that you can have on you network. The key thing you need to remember is that you have different types of Firewalls there is the actual hardware ones which most companies have installed and running and you have the Software install that you can put on you computer. A good example is Zone Alarms. The company I worked for had both of these as security solutions however at that time the only way you could ensure firewall level security was to install and run Black ICE or Zone alarms plus Norton Sysmantec to deal with viruses. Now with the new operating systems there is more security and they do run software such as Windows Defendor which works with other security settings.
So to answer you question "No" network secure does not stop at the firewall and has not for sometime with the improvements in the Operating software plus you can install other programs that help ensure your system is secure.
For additional information check out the site below since it is designed to help new business owners with computer and technology. www.businesscomputingguide.com