This is a typical Microsoft weird issue you might spend weeks trying to figure out and it is as easy as un checking a check box.

Problem: When connected to my internal LAN via VPN client, or through IPSec tunnel I can’t upload FTP files to my internal FTP server. Additionally, when trying to access external FTP servers through my ISA 2006 server, I can not upload.

I scoured my FTP server looking for an issue, when it occured to me I ought to try access from inside the firewall. It worked. Then I searched every access list, cache setting, rule, and property I could think of in ISA 2006.

Finally I found the problem on Tom’s Blog at Lanlogic - Find the rule that applies between your client and the server. This might be the second to last rule, or it might be “allow outbound access to the Internet”. It will be the same rule that sits between you and the FTP server. It probably says “allow all outbound access”. Guess what? It lies.

Right click the rule and LOOK at the drop down, past properties… You will see this. Click the “configure FTP” option. You will see a checked check box that says “Read Only”. Un check it. FTP problem with ISA 2006 solved.

These are the things I love about Microsoft.