FTP Failed to retrieve directory listing when behind a ISA 2006

Symptom using FTP Client or Command Line

You are able to successfully logon to a host using a FTP Client or command prompt but you are unable to retrieve a directory listing or you get Access Denied.  This can happen if your Microsoft ISA 2006 server has the FTP Protocol configured as “Read Only”

Solution

To fix this, logon to your ISA Server Management console and browse to your Firewall Policy.  Right click on your policy and select Configure FTP

Uncheck the “Read Only” option and click OK.

The last step is to Apply the changes to save them.