Trojan (Trojan horse); they are programs consisting of two parts and written for the purpose of remote control of computers.Thanks to this program, even a person who is just starting to use windows can have a lot of permissions on your computer.(Formatting your computer, calmak your account…etc. ).These types of programs are usually used by people who think they are hackers, but there are people who are real hackers and use these trojans, but at this point the size of the incident changes a little, for example, hackers use all trojan-infected computers on the Internet (which are online) to access large sites D.O.They are doing S attacks so that they block access to these sites for a long time, causing great damage to the sites. The first part of these programs serves to control the remote computer, while the other part creates an opening that will allow it to establish a connection between the computer to be managed remotely and the control part Dec.In other words, our problem is related to the part of the trojan program that leaves an open port on our computer.