What port is commonly used for SSH on UNIX-based platforms?

SSH, or Secure Shell, is a protocol used for secure remote login and other secure network services over an insecure network. On UNIX-based platforms, the default port for SSH communications is port 22. This standardization allows network tools and system administrators to configure firewalls, routers, and other devices to allow SSH traffic by designating port 22 for that purpose.

Using port 22 simplifies the process of establishing secure connections, as it is widely recognized by both users and software applications as the default for SSH communication. This contributes to the ease of use and the interoperability of systems and applications that rely on SSH.

The other ports listed serve different purposes: port 135 is typically used for Microsoft RPC (Remote Procedure Call), port 80 is designated for HTTP traffic, and port 443 is used for HTTPS traffic. These ports do not relate to SSH and are not configured for secure shell access, making port 22 the unequivocal choice for SSH on UNIX-based systems.