FTP session where the client issues AUTH TLS to upgrade the connection to TLS and then terminates the session with QUIT without performing further commands. This reflects minimal interaction limited to encryption negotiation and immediate disconnect, commonly observed in capability testing or automated probing.

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.