I'm working with a Green Hills INTEGRITY (v 10.0.2) FTP server. Occasionally, WinSCP will relay a FTP error message:
If "REST 0" is being issued as a keepalive, then this primes the remote system to issue an error on the next command, which WinSCP will present to the user as a pop-up error dialog. Sometimes this appears when navigating to a different directory. Sometimes this appears in the command console as a response to a hand-typed command.Could not retrieve directory listing. STOR or RETR must follow REST.
The pop-up error dialog is a false positive. The machine is still alive and connected, but the dialog demands the user's immediate attention. It is very annoying.
It would be very good for users interacting with this FTP server if either a) there's an option not to use "REST 0" in the assortment of keepalive commands (maybe automatically if GHS INTEGRITY is detected), or b) special handling is put in place to issue "REST 0" and then another keepalive command immediately, then the error response is silently discarded.
Thank you for this software!