what is port 135

TCP Port 135 is the Remote Procedure Call (RPC) Endpoint Mapper service. It is a service that tells other systems what services are listed on a computer and what port to look for them on. Essentially, it allows a system unfettered access to a target system. TCP port 135 is most commonly associated with remote access and management. It is used for RPC client-server communication, and ports 139 and 445 are used for authentication and file sharing. Ports can be opened or closed to permit or stop the transfer of data between devices. If left open, TCP port 135 can potentially let anyone in, which poses a problem with a TCP port 135 vulnerability that can theoretically enable hackers or unauthorized users to access a computer system. Therefore, it is a sensitive port that has a number of security flaws and should never be made available to the internet. However, TCP port 135 is needed in an active directory and server/client environment for many services to operate properly.