Port 110 (POP3)
Post Office Protocol: downloads mail from a mailbox.
- Transport
- TCP
- Internet exposure
- Restrict
Expose only to specific networks, or behind a VPN.
Security notes
- Credentials are cleartext unless using POP3S on 995.
- A frequent target for password spraying against mailboxes.
When it shows up in your logs
Failed logins across many mailboxes from one IP is password spraying.