I am trying to setup a second FTP server on a computer running Windows Server 2008 and IIS 8.0. I already have an FTP server accessible with one port, and this one will be accessible on a different port and point to the same directory.
I forwarded the port on the router and allowed an exception in the Windows Firewall for the new port, after setting it up with Basic Authentication.
Now, I am able to access the FTP server from the local machine using localhost:2020 (pretending that 2020 is my port). When I try using ftp://mydomain.biz:2020, I am still prompted for a login screen, but upon entering the same login information used with localhost, which worked, I receive this error:
How can I fix this error?
Best Answer
This sounds like the stereotypical problem that neither the firewall, nor your router, recognise that you're running the FTP protocol, probably because you're using a non-standard port for the control connection.
When the data connection is announced (the PASV port) that port is possibly not opened by the Windows firewall, making connecting impossible.
Even if the Windows firewall does open the port in the systems firewall, because you're using port-forwarding without specifying the FTP helper module, your router doesn't inspect the responses from the FTP server over the control connection. Then it won't rewrite the internal IP-address of the Windows server to the public IP-address of the router in the PASV response, nor will the router dynamically create the correct port forwarding rule for the data connection.
Grief all around.
check the functioning of the non-standard FTP port from another host within the same network to confirm if the Windows firewall works correctly.
Then check the configuration of your NAT router.