Numerous of the present security systems do not provide satisfactory level of protection aligned with ever- increasing threats. The main reason for their collapse is the use of point solutions to protect hosts and reactive approach against intrusions. Here we studied and apply human immune system, which survives under dynamic changing conditions and provides protection against biological viruses and bacteria. By taking immune system as an analogy, we propose an end-to-end network security system using mobile agents with some mandate. Our solution not only overcomes limitations of traditional security solutions, but also enhances overall security by providing protection at each and every level of attack timeline. But the challenge in implementing such system is how to manage mobile agents in such a way that they are always acting as immune agents for our system. It functions in proactive and also reactive manner and has ability to learn and improve its strategies, equivalent to what human immune system does against viruses and bacteria.