Strange FTP Problem

[Doswelk]

We seem to have a very unusal problem with ftp on IIS4:

We set up an FTP site using prot 1985 and created a username and password and granted the account the right to log on locally. This all worked.

However the reason for setting this all up was cancelled and we removed it all.

Of course it is now required again so we have set it all back up the same and tested it inside the firewall and all was fine, but when we try to access the ftp server over the internet the problems start:

Using the NT ftp "DOS" client we can connect to the ftp server and enter the username and password. All of this works. As soon as we try to put a file or even just type "dir" the message "150 Opening ASCII mode data connection for /bin/ls" is displayed and then it hangs.

This has got us stumped, the fireall is set up with the correct ports open (in fact they were not changed from when it was working before), everything works internally, the FTP server has a valid Internet IP address.

Does anyone have any ideas ?

Thank you

Kevin

 

[Cerati]

Unsure of the exact config of your firewall but FTP needs ports 20 and 21 open for the data and control connections.

Sounds like you're missing a port ?

If you don't filter ports to the DMZ from your internal network, but you do from the internet (and who wouldn't..) and it works internally but not externally it points towards a configuration issue on the firewall, not IIS itself.

 

[epohl]

Definitely sounds like a Firewall problem. Your firewall may be blocking passive transfers. Many FTP Clients including web browsers use passive by default. Try connecting with a client outside the firewall that has passive (PASV) disabled.