Whenever you set up an email app, you'll almost always run into three acronyms: IMAP, POP3, and SMTP. This guide explains what each protocol does, how IMAP differs from POP3, which ports and types of encryption are used, and what to choose for a business.
Who does what
The protocols fall into two groups: some are for receiving mail, and one is for sending it.
- IMAP and POP3 are for receiving: your email app fetches the messages that arrived in your mailbox from the server.
- SMTP is for sending: your app hands the message to your mail server, which then delivers it to the recipient's server.
That's why settings almost always include two servers: incoming (IMAP or POP3) and outgoing (SMTP). The only real choice is between IMAP and POP3. SMTP is used either way.
IMAP: mail stays on the server
With IMAP, messages and folders stay on the server, and your app displays them and syncs changes. Read a message on your phone and it shows as read on your computer too. Move it to a folder in webmail and it's in that folder in Outlook as well.
Advantages of IMAP:
- your mail looks the same on every device;
- sent messages and folders are available everywhere;
- if you lose your laptop, you don't lose your mail, because it's on the server;
- a new device connects in minutes and sees all your mail right away.
The trade-off: messages take up space in your mailbox on the server, so you need to keep an eye on your quota and clean out what you don't need from time to time.
POP3: mail is downloaded to your device
POP3 is an older, simpler protocol. Your app downloads new messages from the Inbox to your computer. Usually they're then deleted from the server, although most apps have a "leave a copy on the server" option.
What to know about POP3:
- it only works with the Inbox, so other folders on the server don't sync;
- read and deleted status doesn't sync between devices;
- messages live on one computer, and if it fails without your own backup, they're gone;
- it uses almost no server space if messages are deleted after downloading.
If you use POP3 and delete messages from the server, your computer is your only archive. The server's shared backups won't help you recover messages that were already downloaded and removed from the server.
Which one to choose
| Situation | Recommendation |
|---|---|
| Email on both a computer and a phone | IMAP |
| You use both webmail and an email app | IMAP |
| Several people read the same mailbox | IMAP |
| You need calendar and contacts synced to your phone | Exchange ActiveSync, or CalDAV/CardDAV alongside IMAP |
| One device, a very small quota, and your own archive on the computer | POP3 (with caution) |
For most companies, IMAP is the right choice. Keep POP3 for the rare cases where it's a deliberate decision.
Ports and encryption
Each protocol runs on its own port. Most offer two ways to secure the connection:
- SSL/TLS (implicit TLS): the connection is encrypted from the moment it opens.
- STARTTLS: the connection starts unencrypted and then upgrades to encryption on command.
Standard ports:
| Protocol | SSL/TLS | STARTTLS or unencrypted |
|---|---|---|
| IMAP | 993 | 143 |
| POP3 | 995 | 110 |
| SMTP (sending from an app) | 465 | 587 |
| SMTP (server to server) | — | 25 |
Port 25 is for relaying mail between servers. Email apps should send through port 465 or 587 with a username and password. Many internet providers block outgoing connections to port 25 for their customers, so don't use it in your email app.
Always turn encryption on. Without it, your username, password, and message content travel in the clear, and anyone with access to the network, such as on public Wi-Fi, could intercept them.
MCMail settings
Most of the time you won't have to type anything: MCMail supports automatic setup (autoconfig and autodiscover), so your app fills in the settings from your email address. If you need to set things up manually, use these values:
| Setting | Value |
|---|---|
| Incoming mail server (IMAP/POP3) | mail.mcmail.uz |
| IMAP port (SSL/TLS) | 993 |
| POP3 port (SSL/TLS) | 995 |
| Outgoing mail server (SMTP) | mail.mcmail.uz |
| SMTP port (SSL/TLS) | 465 |
| Alternate SMTP port (STARTTLS) | 587 |
| Username | Your full email address, such as name@example.uz |
| Password | Your mailbox password |
For SMTP, be sure to turn on authentication (apps usually call this "my outgoing server requires authentication") with the same username and password. If your administrator has turned on two-factor authentication, check with support on how to connect an email app.
Step-by-step guides for specific apps: Outlook, Thunderbird, iPhone, iPad, and Mac, Android.
Common mistakes
- Wrong username. Just the name (
name) instead of the full addressname@example.uz. - Port and encryption don't match. For example, port 465 with STARTTLS, or port 587 with SSL/TLS. The connection fails or hangs.
- SMTP authentication is off. You can receive mail but can't send it.
- The mailbox is full. With IMAP, mail accumulates on the server. Once the quota runs out, new messages may be rejected. Empty the trash and clear out large attachments regularly.
- Too many attempts with a wrong password. After a password change, the old one is still saved on a phone or in another app, which keeps trying to sign in. Password-guessing protection may temporarily block sign-in. Update the password on every device.