In a computer network, an attack is an attempt to destroy or steal unauthorized information or make use of information as an asset. One of the attacks is a reconnaissance attack considered as the first step of a computer attack. This type of attack is mostly done by a black hat, an expert in the programmer, by scanning the internal network devices and gather vulnerability information. In this paper, shows the identification of open ports and services through the network and available IP on the network are possible to attack.

Keywords : Open Ports, Nmap tool, Automatic Scanner, IP