POP3S

POP3S (Post Office Protocol 3 Secure) is a secure email retrieval protocol that operates over port 995. It encrypts the communication between the email client and server, ensuring that the data transferred is secure. This protocol is commonly used to protect email data from interception and unauthorized access.

What is POP3S

POP3S, or Post Office Protocol 3 Secure, is an extension of the standard POP3 protocol that adds a layer of security by using SSL/TLS encryption. This ensures that the communication between the email client and the server is encrypted, protecting the data from being intercepted by malicious actors. POP3S operates over port 995, which is designated for secure POP3 connections.

The primary function of POP3S is to allow email clients to retrieve emails from a remote server securely. Unlike IMAP, which allows for more complex interactions with the email server, POP3S is designed for simple download-and-delete operations. This makes it a suitable choice for users who prefer to store their emails locally rather than on the server.

Historically, POP3 was one of the first protocols used for email retrieval, and its secure variant, POP3S, was developed to address the growing need for secure email communications. Many email service providers support POP3S to ensure that their users' email data is protected during transit. The use of SSL/TLS encryption in POP3S helps prevent eavesdropping, man-in-the-middle attacks, and other security threats.

POP3S runs on TCP and UDP port 995 and is official IANA port.

Security risk

If port 995 is open and the POP3S service is running, the primary risk is related to potential vulnerabilities in the email server software. An attacker could exploit these vulnerabilities to gain unauthorized access to email data. Ensuring that the email server software is up-to-date and properly configured can mitigate these risks.

In our UFW tutorial you can follow instructions how you can configure UFW to close port 995. Use StackChanges to monitor if the POP3S port is closed and stays closed. StackChanges will send an alert if port 995 is open again.