Port 465 (SMTPS (implicit TLS submission))
Authenticated mail submission from clients over TLS.
- Transport
- TCP
- Internet exposure
- Public by design
Normally public, but keep the software patched and hardened.
Security notes
- A target for credential stuffing against mail accounts.
- Compromised accounts are used to send phishing from trusted domains.
When it shows up in your logs
Many authentication failures across accounts is password spraying.