Suddenly users were not able to ftp using FileZilla and only ftp connections were made through the command prompt. When I searched for this issue, I found a couple of questions here in serverfault facing this issue and the reply was because command line uses active mode and the solution was to change the transfer mode in filezilla from passive to active, and this actually worked. I need to know the reason why this happened since it was working fine with the passive mode before, is this something to be configured from the server instead of making all clients change their transfer mode. We are using FTP server on IIS 6.
Thanks in advance