The era in which we live is the prime concern of security. The world has been computerized and protecting data from the attackers is really a crucial task. Several unauthorized network is entering into the authorized network. Designing a secured network is really a tough task. The layers which are affected due to hacking are data link layer and Network layer. This paper discuss 0about the type of attacks done by the attackers and counter measures for the attack. Cisco packet tracer is used to observe the path how data is sent and where data is moving.