The standard port for secure SMTP email transmission is port 587. However, older systems may use ports 25, 465, or 2525.
SMTP Ports Explained
SMTP (Simple Mail Transfer Protocol) uses specific ports for sending email messages. Understanding these ports is crucial for configuring email clients and servers correctly.
Standard Port
- Port 587: This is the recommended port for secure SMTP submissions. It is typically used with TLS/STARTTLS encryption.
Other Ports
- Port 25: Traditionally, port 25 was used for SMTP. However, it's now often blocked by ISPs to prevent spam.
- Port 465: Originally intended for SMTPS (SMTP over SSL), it's now deprecated but may still be found in older systems.
- Port 2525: This port is sometimes used as an alternative to port 587, particularly when port 587 is blocked.
Table of SMTP Ports
| Port | Description | Security | Status |
|---|---|---|---|
| 25 | Traditional SMTP Submission | No Encryption | Often Blocked |
| 465 | SMTPS (SMTP over SSL) | SSL (Deprecated) | Deprecated |
| 587 | Recommended SMTP Submission | TLS/STARTTLS | Standard |
| 2525 | Alternative SMTP Submission | Often Unencrypted | Alternative |
Example Configuration
When configuring an email client, you would typically specify the SMTP server address and port. For example:
- SMTP Server: smtp.example.com
- Port: 587
- Encryption: TLS/STARTTLS
This setup ensures that your email is sent securely.
