IMAP (Internet Message Access Protocol) is the standard protocol used to access and synchronize email stored on a mail server.
Unlike POP3, IMAP is designed for users who access the same mailbox from multiple devices.
With IMAP:
Example:
Mail Server
│
┌────┴────┐
│ │
Laptop Smartphone
│ │
└────┬────┘
│
Synchronized Mailbox
| Port | Purpose |
|---|---|
| 143 | IMAP with STARTTLS |
| 993 | IMAP over SSL/TLS (recommended) |
Today, port 993 is the most commonly used.
Using IMAP, an email client can:
| IMAP | POP3 |
|---|---|
| Mail stays on server | Mail is usually downloaded |
| Multiple devices | Best for one device |
| Synchronization | Limited synchronization |
| Server folders | Local folders |
Modern IMAP connections should always use TLS.
Most providers recommend:
Port 993 SSL/TLS Enabled
The Telenegar Mail Check service can verify: