Web proxy clients cannot download from an FTP server using PASV mode
Symptom: Attempts by Web proxy clients to download from a PASV mode FTP server fail.
Issue: By default, FTP traffic handled by Web Proxy Filter uses Active mode.
Solution: Set the DWORD value NonPassiveFTPTransfer to 0 in the registry on the ISA Server computer, which sets the mode to Passive. The default value is 1, indicating that Active mode is used. For information about setting this registry key, see the Microsoft Knowledge Base article 300641 "How to enable passive CERN FTP connections through ISA Server 2000 or ISA Server 2004 Standard Edition." The registry instructions in this article also apply to ISA Server 2006 and ISA Server 2004 Enterprise Edition.