Passive Mode FTP to Active Mode

[Steve Ferrara]

Guys, A vendor of ours is planning to modify their FTP method from passive mode to active mode and they requested us to check our programs for the compliance with new FTP method.

From a UNIX perspective is there anything I need to check or be aware of?

Thanks

[RAC_1]

You do not need to check anything.
Unix ftp supports both. If you want to be sure, just on unix prompt, do ftp and then help. It will list both passive, active.

Anil

[Steve Ferrara]

I did as you suggested and I don't see active listed, only passive.

[RAC_1]

By default it is active. It won't be seen on help page. Search ftp active passive on google, and you know the difference. Bothhas it's pros and cons.

Anil

[rick jones · Accepted solution]

IIRC the "passive" command in FTP is a toggle - each time you issue it, it flips the sense of active vs passive.

Active vs passive is generally only an issue with firewalls, where passive is generally used so the client can be the one to initiate the data connection - on the premis that the client is "inside" the firewall and the firewall is configured to allow connections from the inside, rather than following FTP state to know when an outside system might have been asked to establish a connection.