The management of network bandwidth is more important along with the population growth of Internet. For the issue of network bandwidth management the first thing needs to be done is to analyze network traffic belongs to which protocol. And then we can restrict the usage of network bandwidth accroding to the mangement policy. The mean used to identify network traffic in the past is port-based one which based on the well-known default port number of application protocols. For example, the Hyper-Text Transfer Protocol (HTTP) uses port number 80 as his default port, therefor we could classify traffic which appears in port 80 as HTTP traffic. It is not enough for applications in our own day, especilly the Peer-to-Peer application that used random port number as his default port in order to evade the port-based classifiaction. In order to conquer the issue described above we developed a content-based protocol classifier which inspects the payload of packets. We also compared our system with other content-based protocol classifiers. In addition, we also provided a verification tool which verifies the result of protocol classifier by connecting to the host and testing the hehavior of specific application.