Port 465 was originally registered for SMTPS (SMTP over SSL). After a brief stint in that function, port 465 was reassigned for a different use and deprecated. Despite that fact, many ISPs and cloud hosting providers still support port 465 for SMTP submission.
Here’s What to Know About SMTP Security All you need to know about secure SMTP SSL ports 587, 25, 465 and 2525, and the roles they play in email security. SMTP Security. In and of itself, SMTP is an insecure protocol. It essentially lacks any real security features, which is... SPF, DKIM, and DMARC: ...
SMTP Settings. Microsoft 365. Outlook. Hotmail. Live.com. Server: outlook.office365.com. Port: ...
So a good solution is to simply change the port to 587 or 2525 (if you’re using an unencrypted connection) and 465 or 25025 for a SSL connection. Remember anyway that only a professional SMTP service can guarantee the highest delivery rate, avoiding completely all these sending problems.
When an email client or outgoing server is submitting an email to be routed by a proper mail server, it should always use SMTP port 587 as the default port. This port, coupled with TLS encryption, will ensure that email is submitted securely and following the guidelines set out by the IETF.
The default SMTP port number is : 25. Secondary SMTP port number : 26. SMTP over SSL/TLS port number: 465
Because data can be sent with or without the use of SSL, one way to indicate a secure connection is by the port number. By default, HTTPS connections use TCP port 443. HTTP, the unsecure protocol, uses port 80.
If you want to connect SMTP service to send an email, you need to provide an SMTP IP address, Port number and login credentials. SMTP Port Numbers > The default SMTP port number is : 25