I have a issue i can connect to the IIS ftp service on my Local Network 192.168.x.xx but if i TRY to connect to it externally 80.xxx.xxx.xxx (through internet) i get the 425 error i'm using a 2xxx portinstead of the port 21 normally used for ftp(security reasons) added the exception to Zone Alarm(might have done it incorrectly) AND to my router (portforward) but all have no effect. turning ZA of prevents me from even connected to the ftp locally but if its turned on locally atleast works tried passive and active client SETTINGS using fireftp and android app called"fileExpert"both WORK locally but not over the internet...http://support.microsoft.com/kb/129395That did not really help at allFTP error 425 is a socket error. This means that the client can't OPEN a data connection. You have a FIREWALL problem which is not letting the client open the 2nd port needed for FTP to transfer the data. This gives your client a 425 error.

Try to make sure your firewall is setup for port 21 and the client is using pasv mode.

Microsoft doesn't like non-standard ports. If you want a FTP server to work with another port number you need to look at another FTP server software.

FileZilla works good and its free....
http://filezilla-project.org/