Question : FTP Access denied 550 only from inside the office network... same credentials work externally

I'm having an issue editing/uploading files to our externally hosted FTP site (gogax).

The logs in ISA show that the initial connection is made, and accepted, but other than that, there is nothing that is being denied. I'm not sure where to look beyond that, maybe the ISP? There is a Cisco router between ISA and the ISP which is the prime suspect at the moment, and I was hoping that someone could suggest additional troubleshooting options.

Here are examples of connecting from the office, and the identical request from home:

Request from in the office
ftp> open XXXXXXXXXXXX.com
Connected to XXXXXXXXXXXX.com.
220 Microsoft FTP Service
User (XXXXXXXXXXXX:(none)): XXXXXXXXXXXX
331 Password required for XXXXXXXXXXXX.
Password:
230 User XXXXXXXXXXXX logged in.
ftp> cd XXXXXXXXXXXX.gogax.com
250 CWD command successful.
ftp> cd downloads
250 CWD command successful.
ftp> put c:\test01.txt
200 PORT command successful.
550 Access is denied.
ftp>


Identical request from Home PC
ftp> open XXXXXXXXXXXX.com
Connected to XXXXXXXXXXXX.com.
220 Microsoft FTP Service
User (XXXXXXXXXXXX:(none)): XXXXXXXXXXXX
331 Password required for XXXXXXXXXXXX.
Password:
230 User XXXXXXXXXXXX logged in.
ftp> cd XXXXXXXXXXXX.gogax.com
250 CWD command successful.
ftp> cd downloads
250 CWD command successful.
ftp> put  c:\test01.txt
200 PORT command successful.
150 Opening ASCII mode data connection for test01.txt.
226 Transfer complete.
ftp: 4 bytes sent in 0.00Seconds 4000.00Kbytes/sec.
ftp>

Answer : FTP Access denied 550 only from inside the office network... same credentials work externally

Hi, ISA WILL block uploads to FTP servers.

To configure FTP filtering

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. (You would deselect This)

Note
To open ISA Server Management, click Start, point to All Programs, point to Microsoft ISA Server, and then click ISA Server Management.