May 29 2017
Determine Operating System within FTP Session
The “QUOTE” keyword is essential to allow a user to run system-specific commands on FTP servers (SITE or ALLO for example). These commands do not have to be understood by FTP clients.
Most FTP clients send a NOOP – that actually is a dummy packet – to keep the connection up
ftp> quote noop
200 NOOP ok.
QUOTE SYST returns the Operating System the FTP server runs on, or at least gives you a hint.
Check these 2 examples on Linux Redhat and IBM i, the second giving a lot more details than the first with the exact version of the operating system.
ftp> quote syst
215 UNIX Type: L8
ftp> quote syst
215 OS/400 is the remote operating system. The TCP/IP version is "V7R1M0".