I just installed FileZilla Server to replace our old Ipswitch FTP software. I configured it to use the same SSL cert, listen on port 990 and only accept SSL, bind to the external IP, etc. Pretty much the same configuration as the previously functional Ipswitch software. Problem is: when the same exact client connects to the server, they never see the "220 Banner msg". The server management console claims it is sent, I've been watching with Wireshark and I do not see it being sent. All I see is the three-way TCP handshake and teardown. Any ideas why it would not actually send the packets?
Well that's frustrating... you need to tell the server not only that it should listen to 990 for SSL, but it should listen in general on 990, even though it complains that the port is already in use if you do so. Anyway, it's happy now. :)