How to apply Username and Password for Network Drive?

[Saint Elsewhere]

I am trying to save a report in a network drive "Z:" (ftp).

string LogFileName = @"\\10.100.64.17\ftp-share\TEST\" + strDateTimeStamp + @"\TestReport.xml";

How can I add UserName and Password for access to save in that folder on the network drive? In some machines it asks for password, in some machines its already connected so doesnt ask for password.

Thanks in advance.