Using Active (PORT) Mode FTP Programs from Behind the ISA Firewall
A number of people have had problems with connecting to FTP sites using Active Mode when behind the ISA Firewall. The problem is mostly seen when the Firewall client is installed, the Enable folder view for FTP sites is enabled in Internet Explorer and the Use Passive FTP checkbox is not selected in Internet Explorer.
The problem doesn’t happen if you use the built in FTP client (ftp.exe) that comes with Windows or when the Firewall client isn’t installed and the machine is configured as a SecureNAT client.
Microsoft has a hotfix with a file version dated 9/20/2004, so I suspect that if you installed ISA 2004 SP2, you’ll have the fix, since my file version is dated 1/18/2006.
For more details, check out the KB article at http://support.microsoft.com/kb/884580/en-us
HTH,
Tom
Thomas W Shinder, M.D.
Site: www.isaserver.org
Blog: http://blogs.isaserver.org/shinder/
Book: http://tinyurl.com/3xqb7
Email: tshinder@isaserver.org
MVP — Microsoft Firewalls (ISA)
Jeff Fiorino Says:
November 30th, 2006 at 5:22 am
Dear Thomas,
I have isa-server “inside” a sbs2003, and sinds i installed sp2 for isa-server i have this problem with active FTP. I tried the hotfix 884580, but i can’t install it, it says that i have a different version of the program. MS is aware of this and is working on it, few weeks now,
Jeff
Alex Chong Says:
May 29th, 2007 at 10:38 pm
Hi Tom,
I’m experiencing the same issue with an ISA 2006 box. The systoms are exactly the same as per your description and Microsoft article. Would you know whether this is a Microsoft problem? or any workaround solution on this issue. thanks a lot
Alex
Thomas Shinder Says:
May 30th, 2007 at 6:16 am
Hi Alex,
You might need to configure the ISA Firewall to use PASV instead of PORT mode with a Registry setting.
HTH,
Tom