465/TCPSMTPS (Submission über TLS)
Email · Well-known port · OSI layer 7
Send mail from an email client to your own server directly over TLS (implicit TLS).
IANA: officially registered as submissions
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Port 465: SMTPS for encrypted mail sending
Port 465 (TCP) is used to send mail with authentication and implicit TLS, often called SMTPS. The tool shows you the details and generates firewall commands for the port.
Built by Justin Schuessler
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Ports
Firewall rule (inbound)
Firewall commands
Open port
sudo ufw allow 465/tcpNotes on ufw
For Ubuntu and Debian. ufw creates the rule for both IPv4 and IPv6. If ufw is disabled, allow SSH first (sudo ufw allow 22/tcp), then enable it with sudo ufw enable, or you'll lock yourself out.
On a ZAP-Hosting VPS with an active network firewall, you also need to allow the port in the Customer Panel.
Port 465 explained
What is port 465 used for?
Purpose
On port 465, email clients and applications submit emails to their mail server, just as they do on port 587. The difference is that the connection is encrypted with TLS from the start, with no unencrypted initial connection or STARTTLS. The client then authenticates with a username and password. Many email providers label this setting SSL/TLS in email clients.
Origin and standard
Port 465 was briefly registered for SMTP over SSL in the 1990s, but the registration was withdrawn because STARTTLS on port 587 was intended to be the standard approach. In practice, many mail providers continued to use port 465. RFC 8314 from 2018 therefore officially registered the port again for mail submission with implicit TLS. IANA has listed the service as “submissions” since then.
Typical use
- Sending from email clients configured for SSL/TLS
- Sending email from applications and scripts over an encrypted connection
- Sending mail on networks where proxies interfere with STARTTLS
Security
Implicit TLS has one advantage: an attacker cannot simply prevent encryption, as is possible with a STARTTLS downgrade. Use a valid certificate and disable outdated TLS versions. Only accept mail from authenticated users here too, and limit failed login attempts, for example with Fail2ban. You only need to open port 465 for incoming traffic on your own mail server.
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Related ports
These ports are often part of the same setup. Click one to see its explanation and firewall commands.
View all well-known ports and the complete IANA list
Port list source: IANA Service Name and Transport Protocol Port Number Registry, as of October 22, 2026. iana.org
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FAQ
Frequently asked questions
Quick answers about port 465.
If both work, port 465 with implicit TLS is recommended by RFC 8314. Port 587 with STARTTLS is just as common and secure, provided STARTTLS is required. If in doubt, use the port specified by your mail provider.
No. Port 465 was considered outdated for a while, but RFC 8314 officially registered it again in 2018 for mail submission over TLS. It is now a standard, recommended port.
In most mail clients, the SSL/TLS setting means implicit TLS, which uses port 465. STARTTLS uses port 587. If you choose the wrong combination, the connection will usually fail with a timeout or certificate error.
With ufw, sudo ufw allow 465/tcp is enough. With firewalld, run sudo firewall-cmd --permanent --add-port=465/tcp followed by sudo firewall-cmd --reload. Only open the port for incoming traffic on the server running your mail server.
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