· Apr 4, 2022

FTPS TLS session resumption

We are attempting to update some old FTP interfaces to use FTPS and having an issue with an outbound operation to a FileZilla server.

The connection to the the server works, however it fails to transfer files with the error "TLS session of data connection not resumed."

It appears that "TLS session resumption" is no longer optional in FileZilla Server, and I cannot find any details in the IRIS documentation about it.

Does IRIS support TLS session resumption, or know how to set up FTPS to a recent install of FileZilla Server?

Product version: IRIS 2021.1
Discussion (3)1
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Hi Elisha,

I happened to have worked on a somehow similar request recently, even if not with the use of the FTP adapter within a production, but with the %Net.FtpSession class directly.

The short answer is probably that we do have support for the "new" SSLUseSessionResumption property, starting with the IRIS 2022.1 release.
The matching documentation in the  %Net.FtpSession class:

property SSLUseSessionResumption

Using the 2022.1 release, and the %Net.FtpSession class, you could adapt your code to include an extra set on the matching property, like "set ftp.SSLUseSessionResumption = 1"

In order to use the same property within the FTP adapter, it gets a bit more complex:
the matching change will come into the product with the 2022.2+ releases.

I would suggest that you perform a quick test using the %Net.FtpSession class in a 2022.1 installation, just to confirm that the use of the SSLUseSessionResumption property will allow the code to connect to your specific SFTP server.

Once you have that confirmed, you will probably want to open a WRC Support request to see if the change could be made available into your current release.