1. Explain the function of a Mail User Agent (MUA)? Please provide at least one example of a MUA?

A mail User Agent (MUA) allows the receipt and the transfer of email messages. The MUA is installed in the computer and used to download and store email messages in the computer. It also allows email messages to be read on an offline mode. An example of a MUA is Yahoo, which is used to access and manage a user’s email.

2. Explain the function of a Mail Transfer Agent?

The Mail Transfer Agent (MTA) is a program that transfers emails between clients. Specifically, it transfers and routes electronic mail messages from the sender’s computer to the receiver’s computer. The MTA receives mail from another MTA of an MUA, and if the receiver is not hosted locally, the message is forwarded to another MTA until it is delivered to the message delivery agent.

3. Explain the function of a Mail Delivery Agent?                                                                 The Mail Delivery Agent is a computer software that delivers email messages to the mailbox of a local recipient. It is prompted by the MTA to store messages in the recipient’s mailbox. MDA is protected by a login and passwords that protect users’ messages from being checked by unauthorized users.
4. Define the name and function of layer 7 of the OSI model?

The seventh layer is known as the application layer, and it supports application and user-end processes. All the activities in this layer are based on application. The layer provides application services for email, file transfers, and other network software services. This layer generates real traffic data such as web requests from HTTP protocol or a file download request from a FTP protocol.