Passive FTP results in zero byte file

Posted on 2014-08-19
Last Modified: 2015-05-29
I am running FTP using IIS 8 on Windows Server 2012.

I have an FTP site that I can successfully send files in using active FTP mode but if I use passive mode to the same site with the same FTP account credentials I see the file appear in the folder with a zero byte size for a second or two and then the file disappears.

This is running in an AWS environment.

I have configured a port range in the FTP Firewall Support settings on IIS for this site and the FTP server has an AWS security group with the same ports allowed inbound from any address.

Can anyone help ?

Question by:ccfcfc
    LVL 10

    Accepted Solution

    When you are using passive mode, it is the client initiate connection and the server tells the client which port it is listening to. If ftp works in active mode but not in passive mode, please check firewall settings on the server side. A beautiful article which would further help you to troubleshoot can be found here.

    Author Comment

    Thanks for the response. I will take a look at the article.

    If I have configured the FTP server for ports 49152-65535 and I have allowed those ports access from any IP address should that not be working ?

    How can I confirm what port the FTP server has told the client to use ?
    LVL 10

    Expert Comment

    How are you connecting to the server? Which FTP client? Use debugging as you may have noticed in the example in the aforementioned article you will see the response

    227 Entering Passive Mode (192,168,150,90,195,149).

    So I would think the listening port is 195*256+149

    Author Comment

    I connect using DOS and simple FTP command line

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