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Network+ Exam

Email ports and Protocols.

October 29, 2025

  • #network+

Email ports and Protocols.

what the server uses to send emails.

SMTP over port 25 plain text

SMTPs is the secure variant, tunneles it through smtps.

port 465 or port 587 to ensure they are encrypted.

POP3 post office protocol version 3

used to retrieve emails from a remote server to a local client port 110. you download the emails to the computere this was better from dialup. at first it was deleting to the emails off the server. Iinsure protocol.

IMAP -Internet message access protocol. port 143 allows you to manaage emails directly on the email server designed for the alwasy on email, best if you check email from multiple locations.

IMAT initally lacked security, transmitting over in plain text

IMAPS port 993 is secure, uses an SSL or TLS tunnle.

SMTP/SMTPS sending emails

POP3/IMAP used for reciving emails.

alwasy use the secure verison of the protocols.

📧 Email Protocols — Server Use, Ports & Security

🔼 Sending Email (Server to Server or Client to Server)

| Protocol | Port | Secure? | Notes | | --- | --- | --- | --- | | SMTP | 25 | ❌ No | Sends email in plain text. Used mostly server-to-server. | | SMTPS | 465 or 587 | ✅ Yes | Secure SMTP using SSL/TLS. Used by clients to send mail securely to servers. |

✅ Always use port 465 or 587 over 25 for secure sending.

🔽 Receiving Email (Client from Server)

| Protocol | Port | Secure? | Notes | | --- | --- | --- | --- | | POP3 | 110 | ❌ No | Downloads email to local client; deletes from server by default. Ideal for dial-up era. | | POP3S | 995 | ✅ Yes | Encrypted version of POP3 using SSL/TLS. | | IMAP | 143 | ❌ No | Allows users to manage email on the server. Best for multi-device access. | | IMAPS | 993 | ✅ Yes | Secure IMAP using SSL/TLS. Recommended over IMAP. |

🔐 Summary Table

| Action | Insecure Protocol (Port) | Secure Protocol (Port) | | --- | --- | --- | | Send Email | SMTP (25) | SMTPS (465 or 587) | | Receive Email | POP3 (110), IMAP (143) | POP3S (995), IMAPS (993) |

💡 Memory Tricks

  • SMTP = Sending
  • IMAP = Server Management (Multiple devices)
  • POP3 = Pull once and delete (Download & store locally)

✅ Must Know for the Exam

  • Always prefer SMTPS, IMAPS, and POP3S for secure communication.
  • Ports:
    • 25 / 465 / 587 → SMTP
    • 110 / 995 → POP3
    • 143 / 993 → IMAP