Solution to FTP Upload Problem with ISA Server 2004

As a new user of ISA, I had a very annoying problem. I was unable to upload any file from my new website using FTP. I kept getting Error 550, Access denied. every time I tried to create a new folder or upload a file using SFTP or FTP.

Finally, it turns out that ISA Server 2004 has an option to restrict FTP uploads. Unfortunately this option has been set for both directions (FTP sessions initiated from both inside and outside the internal network).

To find that (somehow hidden) option that enables the restriction was another issue. Here is how to fix it:

1. In the console tree of ISA Server Management, click Firewall Policy.
Where?

Microsoft Internet Security and Acceleration Server 2004
Server_Name
Firewall Policy
2. In the details pane, click a server publishing rule or access rule that applies to FTP traffic.
3. On the Tasks tab, click Edit Selected Rule.
4. On the Traffic tab (for a server publishing rule) or on the Protocols tab (for an access rule), click Filtering, and then click Configure FTP.
5. On the Protocol tab, select Read Only, if FTP uploads should be blocked. Otherwise make sure the checkmark is removed(FTP filtering is set to Read-only by default!).