Network security consists of the provisions made in an underlying computer network infrastructure, policies adopted by the network administrator to protect the network and the network-accessible resources from unauthorized access, and consistent and continuous monitoring and measurement of its effectiveness (or lack) combined together.
So what does that me for you a small business owner
Unless you want a full time job in I.T. you are going to need some help. You have an accountant for tax questions and a laywer for legal question and a financial advisor for finacial advise - well now you are going to need an I.T. professional to help with security. Just don't pick the wrong one because just like bad legal advise can get you into trouble, bad network security can be very dangerous too.