1. Explain the function of the SMTP protocol? What are the recognizable and preferred TCP ports?

The Simple Mail Transfer Protocol (SMTP) is an internet standard for email transmissions. The standard was introduced in the 1970s, and it occurred due to a need to have integrated email communication among users of different systems. SMTP moves emails on and across networks so that they can be sent to the right email address. The recognizable TCP ports are the ends of logical connections that transfer data, and they provide services to unknown clients. The recognizable and preferred TCP ports are port 25 and port 465.

2. Explain the function of the POP protocol? What are the recognizable and preferred TCP ports?

The Post Office Protocol (POP) is a standard mail protocol that is used to receive emails from a remote server to a local email client. It provides the functionality of downloading emails and reading them when offline. Messages can be stored on an individual’s local computer, therefore reducing the space used by the email account on the web server. The recognizable and preferred TCP ports are port 110 and port 665.

3. Explain the function of the IMAP protocol? What are the recognizable and preferred TCP ports?

The Internet Message Access Protocol (IMAP) is used to access email on a remote web server from a local client. It is supported by modern email clients and web servers. IMAP is different from POP in that it allows concurrent access by numerous clients. The recognizable and preferred ports are port 143 and port 993.