Port 143 (IMAP)
Internet Message Access Protocol: mailbox access that keeps mail on the server.
- Transport
- TCP
- Internet exposure
- Restrict
Expose only to specific networks, or behind a VPN.
Security notes
- Credentials are cleartext unless using IMAPS on 993.
- Legacy IMAP authentication often bypasses multi-factor authentication.
When it shows up in your logs
Logins from unexpected countries or many accounts at once suggest password spraying.