Dear,
What is being used for Data encryption & secured authentification in FTP
How to configure secure FTP(SFTP)
I have W2K server
IIS 6.0
I have Configured FTP in IIS, Not used any FTP software server/client
Please guide.

Note:- I do not have VPN channel
Does SSH or IPSec helps me?

IIS6 does not support SFTP or FTPS. IIS7 reportedly will at some point.

SFTP requires a specific client that will support SFTP (like PuTTY). Using FTPS (FTP with SSL) is more widely supported. You will need to setup Certificate Services so you can issue your own security certificate or you will need to purchase a certificate.

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