see below

We saw that a mailbox tied to a particular process on a system is called a port; each port is identified by a number. So, for example, the port to which to direct a request for a web page is number 80. What port numbers are used for a. ssh (secure shell logins)? b. smtp (simple mail transfer protocol)? c. ntp (network time protocol)? Are these port numbers the same across standard Internet-connected systems