Over the years, with every passing day, the communication systems are increasing in size, complication and laterally the users are also being improved successively. Due to this reason the traffic congestion in the communication network has also raised rapidly. Hence it is necessary to keep an eye on every node in the network, packet sniffer is used. Sometimes a packet sniffer is called a network monitor or network analyser. Many system administrator or network and security administrator use it for monitoring and troubleshooting network traffic. Packet sniffers are convenient for both local area network and radio environment networks. In this paper we have describe the nuts and bolts of packet sniffer, and the workings in both local area network and radio environment networks, outbreak and refuge

Keywords : Protocols, Packet Sniffer, OSI Model,Credencials