A system and a method for server recording and client playback of computer network characteristics. In general, the network simulation system of the present invention includes a recording module that resides on a server and records and stores the network characteristics associated with networks sessions in a data collector file. The system also includes playback module that resides on a client receives the data collector file and plays back the data collector file upon request. The data collector file includes a log file, which is used to store initial request data, and a data file, which is used to store data other than the initial request data. The method of the present invention includes recording computer network characteristics on a recording server and playing back the recording on a client to the same or another server. The recording method of the present invention includes using a global filter residing on the server to record the network characteristics and storing the recording in a data collector file. The playback method includes receiving a data collector file containing recorded network characteristics recorded on a server and playing back the data collector file to simulate the characteristics of real-world network sessions.