65,536. According to 256*256, the port number starts from 0 to 65535. Usually, the web pages that users can access are called public networks, and each public network will have a fixed IP, so the number of ports that users can access is 65,536. There is a tape access port (CAP) in the tape library: there is a standard 26-slot CAP in the storage TEKSL 3000 modular tape library system.