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.

Identifies HTTP requests targeting the web server root path ("/"), typically used for initial service discovery, host validation, or baseline content inspection prior to deeper enumeration.

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.

HTTP request using GET method.

Identifies HTTP GET requests directly targeting the /bad-request path, indicating automated or manual probing of application error-handling routes rather than legitimate navigation flow.