Active FTP vs. Passive FTP

[kberson]

I know the difference between active and passive FTP (there's an excellent definition here: Active vs. Passive FTP), but what I want to know is: Is there a way to determine what is set up on the server you are on?

I have a monitoring client that we install at our customer sites; it send us server information and logs via FTP. As part of the set up, I have the installer run an FTP test - it makes a connection and transfers a file. The test assumes active FTP and sets a two minute timer; if the timer goes off, then it retries using passive (if both fail, then there's a whole different issue).

This seems slow -- there should be a way to determine before the test how FTP is configured. Does any one know a way?

[Krishnaa]

You mean whether the FTP server allows active FTP or not ?? I believe all FTP servers always allow both the types, it's just the client side firewalls which block active FTP's incoming connections. So it's like knowing if your n/w allows incoming connections from outside, am I getting it right ?

[MikeAThon]

Yes, that seems right. Passive vs active FTP is an issue of the network architecture on the client side. Passive addresses the situation where the client side would not allow new incoming connections from the FTP server, for whatever reason (usually firewall or NAT).

Mike