The main email servers are SMTP (for sending email), IMAP, and POP3 (for receiving email), and they use specific ports to communicate securely over the internet. SMTP commonly uses ports 587 and 465, IMAP uses 993, and POP3 uses 995 for secure connections. Choosing the correct server type and port is essential to ensure reliable, secure email delivery and access across devices.
SMTP: The Outgoing Email Server
What Is SMTP?
SMTP (Simple Mail Transfer Protocol) is responsible for sending emails from your device or application to the recipient’s mail server. Every email you send—whether from Gmail, Outlook, or a website contact form—uses SMTP.
SMTP does not store emails. Its only job is to deliver them to the next server.
Common SMTP Ports
Port-587 (Recommended)
Port-465
Port-25
Best Practice:
Use SMTP port 587 whenever possible for maximum compatibility and security.
IMAP: The Modern Incoming Email Server
What Is IMAP?
IMAP (Internet Message Access Protocol) allows you to read emails directly from the server. Messages remain stored on the server and sync across all devices.
This is why IMAP is ideal if you check email on:
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Phones
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Laptops
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Tablets
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Multiple computers
Common IMAP Ports
Port 993 (Secure IMAP)
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Uses SSL/TLS encryption
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Industry standard
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Strongly recommended
Port 143
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Non-encrypted
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Rarely used today
Best Practice:
Always use IMAP port 993 for secure access.
POP3: The Traditional Incoming Email Server
What Is POP3?
POP3 (Post Office Protocol version 3) downloads emails from the server to a single device and often deletes them from the server afterward.
POP3 works best if:
However, POP3 is becoming less popular due to limited syncing.
Read More: What Are the Main Email Servers and Which Ports Do They Use?
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