Several common port numbers on Windows

139 port 139 is a TCP port that works when you access shared files or shared printers on your local area network through your network Places. 139 ports can become a great security vulnerability once exploited by an attacker on the internet. Because if the hacker is connected to the target host's port 139, it is possible to browse all the shared information in all workstations in the specified network segment, and even make various edits and deletions to the shared folder in the target host, if the attacker also knows the IP address of the target host and the login account. It is also easy to see the hidden shared information in the target host 445 port 445 is also a TCP port, which plays the same role as 139 ports in Windows 2003 Server or Windows Server System. Specifically, it also provides file or printer sharing services in a local area network. However, the port is based on the CIFS protocol (Universal Internet File System protocol), while Port 139 is a shared service provided externally based on the SMB protocol (the server Protocol family). Similarly, an attacker can connect to a 445 port to obtain a variety of shared information within a specified LAN

3389-Port Remote Desktop is 3389

Several common port numbers on Windows