Q.Which protocol out of the following is used to send and receive emails over a computer network? (A) PPP (B) HTTP (C) FTP (D) SMTP

Email Protocol Types

Think of sending a physical letter. You write it, put it in an envelope, address it, drop it in a post box, and eventually it reaches the recipient. But what happens in between? The postal service has rules — how to sort mail, how to route it, how to deliver it. Email works the same way, except the "postal service" is a set of rules called protocols. These protocols are the agreed-upon languages that email clients (like Gmail, Outlook, or Apple Mail) and email servers use to talk to each other.

There are three main protocols you need to know: SMTP, POP3, and IMAP. Each handles a different part of the email journey.

SMTP — The Sending Protocol

SMTP stands for Simple Mail Transfer Protocol. Its job is straightforward: it pushes your email from your device to the recipient's mail server. When you hit "Send," your email client hands the message to an SMTP server, which then finds the recipient's mail server and delivers it.

SMTP only handles outgoing mail. It does not manage how you read or store emails once they arrive. Think of it as the postman who picks up your letter from your home and takes it to the recipient's local post office. Once the email reaches the destination server, SMTP's job is done.

POP3 — The Download Protocol

POP3 stands for Post Office Protocol version 3. This is the older, simpler way to receive emails. When you check your email using POP3, the server downloads all new messages to your device and deletes them from the server (by default). After that, your emails live only on your computer or phone.

This works well if you use a single device and want to save storage space on the server. But it has a major downside: if you check your email on your phone, then later open your laptop, the messages you already downloaded are gone from the server. You cannot see them on the laptop unless you configure POP3 to "leave a copy on the server" — which some services allow.

IMAP — The Sync Protocol

IMAP stands for Internet Message Access Protocol. This is the modern standard. Instead of downloading and deleting messages, IMAP keeps all your emails on the server. Your device only displays a copy. When you read, delete, or move an email, the change happens on the server, and every other device sees the same update.

IMAP is like having a shared locker at the post office. You can open it from your phone, your laptop, or a friend's computer — and you always see the same letters inside. Nothing is removed unless you explicitly delete it.

This makes IMAP ideal for people who check email on multiple devices. It also means your emails are backed up on the server, so if you lose your phone, you haven't lost your messages.

How They Work Together …