Re: FTP environment variable

Patrik -

Thanks for your response. Our use case is that a vendor uses FTPS to
transfer data to our IBMi. FTPS uses ephemeral ports for data. Our
firewall guys aren't going to open all ports for data (with good reason) so
we're looking into using the environment variable on IBMi to limit the
ephemeral ports to 5 or 10 ports.

Thanks,

Steve McKay
(205) 585-8424
samckay1@xxxxxxxxx



On Thu, Feb 12, 2026 at 11:05 AM Patrik Schindler <poc@xxxxxxxxxx> wrote:

Hello Steve,

Am 12.02.2026 um 17:58 schrieb Steve McKay <samckay1@xxxxxxxxx>:

In this example, only 5 ports are available for FTP which means you are

limited to 5 concurrent FTP sessions.

This is wrong. It means that you are limited to 5 concurrent *transfers*.
Remember, FTP opens a separate TCP connection for each data transfer.
Put/get as well as ls!

Is anyone using this environment variable? Is there any impact to your

operation? Any specific issues that you saw? Any tips or caveats?


Can't answer your precise questions. I assume this is to counter some
"special" cases of firewall-foobar which don't/can't inspect the initial
port 21 connection of FTP for the dynamically derived data port. FTP/S (TLS
encrypted FTP) comes to mind.

:wq! PoC


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