Port 993 (IMAPS)
IMAP over TLS: encrypted mailbox access that keeps mail on the server.
- Transport
- TCP
- Internet exposure
- Public by design
Normally public, but keep the software patched and hardened.
Security notes
- Legacy authentication can bypass multi-factor authentication.
- A common target for password spraying.
When it shows up in your logs
Logins from unusual locations or many accounts at once suggest spraying.