How port 445 is used in trust creation

In order to create a trust between two domains, you need to have TCP port 445 (the Microsoft SMB port) open on both sides. Having open ports though (especially for SMB traffic) is an invitation to attacks by worms and other malware, so the few ports you need to keep open the better, right?

What’s not often known though is that once the trust has been established between the two domains, port 445 can then be closed since the port only needs to be open during trust creation. See Domain and Forest Trust Tools and Settings for details.

Article written by MyComputerAid.com