Port 465: SMTPS
SMTP over implicit TLS.
- Port
- 465
- Protocol
- TCP
- Service
- SMTPS
- Exposure
- Expose only with access controls
What is port 465 used for?
Mail submission from clients.
Is it safe to expose port 465 to the internet?
Require authentication. Expose only on your mail server.
If port 465 seems closed or unreachable
- Check that the SMTPS service is running and listening on port 465, not only on 127.0.0.1.
- Check the firewall on the host itself (Windows Defender Firewall, iptables, nftables, ufw) for a rule that allows TCP 465.
- If the host is behind a router, confirm the forwarding rule points to the correct internal address and that your internet provider does not use carrier-grade NAT.
- Test from outside your own network. A port can be open locally and blocked at the edge, or the other way round.
Using port 465 safely
Port 465 can be exposed when the host exists to provide this service, but add controls: restrict source addresses where you can, require strong authentication and encryption, and monitor the logs for repeated failures.
Check whether port 465 is open on your host
The check connects from our server, so it shows what the internet can reach.
Open the port checker