Client sends RTSP OPTIONS requests to check supported methods and confirm that an RTSP service is exposed, then disconnects without attempting authentication or stream setup. This pattern is typically associated with automated reconnaissance or internet-wide scanning rather than active stream access.

FTP session where the client issues AUTH TLS to upgrade the connection to Transport Layer Security. This reflects protocol-level encryption negotiation prior to further interaction.

Automated SMTP interaction performing a minimal capability check by issuing EHLO followed by a STARTTLS upgrade request and immediately terminating the session. This pattern is commonly associated with internet-wide scanners, security research crawlers, or opportunistic bots verifying whether an SMTP service supports encrypted communication. The absence of authentication attempts or message submission indicates reconnaissance or service fingerprinting rather than active abuse.