High Quality Content by WIKIPEDIA articles! A Hack Trapper is an application run on a sometimes deliberately unprotected machine or network with the intention of alerting the user of connection attempts. A Hack Trapper listens on certain ports which are commonly used to gain unauthorized access to a machine or data on it. When a connection is made, the user is alerted in some way. In most cases the source IP address is logged to help trace the connection. Some of these ports include Remote Desktop Protocol, Windows File Sharing, NetBIOS, as well as many Trojan Horses and Backdoors.