FTP Connector throwing IOException: Host attempting data connection is not same as server

I am trying to configure a workflow to connect to an FTP server using the FTP Connector. The connection is using Explicit FTPS on Port 21 with a username and password.

It appears to work when I run only the FTP Connector, and I can view the “FTP File System Connection” output which shows Connected (fs_category [xstring] → CONNECTED).

However, when I connect the FTP connector node to a List Files/Folders node, the second node throws this error:

IOException: Host attempting data connection x.x.x.x is not same as server x.x.x.y

I also get this error if I try to Browse the working directory (from within the FTP Connector settings dialog).

Addition information: the remote FTPS server appears to be hosted on Amazon and behind a Load Balancer. Unchecking Verify hostname and/or Reuse SSL session options do not fix the issue. I have searched and found others with similar issues, but not within the KNIME community. It looks like it might be a bug in the org.apache.commons.net library? The file in my plugins folder is org.apache.commons.net_3.7.2.v20201106-knime.jar.

Finally, I am running KNIME 5.2 and everything is up to date. Also, I am able to connect to the remote server with winSCP without issue.

Any ideas what is causing the issue or a workaround? Or has anyone else had the same issue?

Thank you.

1 Like

Hi @brownm_etx and thank you for reporting this issue.
Yes, you are right and it seems this is an issue with the apache commons net library:

I created a ticket for this problem: AP-21781


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