I don't think that you mentioned what kind of FTP you are using, but let's
assume unencrypted with the initial connection over the default port (21).
My suggested approach for you would be:
1) First try with "passive mode" enabled in Filezilla (Edit/Settings)
2) Verify that the FTP server is working from the same LPAR.
>From the same LPAR, use the FTP client (either batch / TSO / Unix shell), to
>connect to the same **ip address** that your Windows client is targeting.
>> There must be some kind of network issue ( route, firewall, etc) <<
3) Verify network from the Windows client with "tracert" (google it)
If this works, skip to step 5
4) If "tracert" doesn't work, it could be that ICMP packets are being blocked
on on your path.
Try tracing packets using the port (21)
Download the "tracetcp" tool for Windows (google it) and try that.
if you run it and there's a problem, get the info to your network team.
5) There could still be a firewall problem.
In Filezilla "Edit/Settings", enable "4 - Debug" level logging.
Try the connection and get the trace information to your network team to
look at.
Kirk Wolf
Dovetailed Technologies
https://coztoolkit.com
On Sun, Jul 27, 2025, at 8:11 AM, Support, DUNNIT SYSTEMS LTD. wrote:
> MVS TCP/IP NETSTAT CS 3.1 TCPIP Name: TCPIP 13:08:03
> User Id Conn State
> ------- ---- -----
> FTPSERVE 00000013 Listen
> Local Socket: ::..21
> Foreign Socket: ::..0
>
> This is what it should be, right?
>
> Keep in mind my problem is with FileZilla. I can run FTP batch jobs on z/OS
> to get/put files on external Internet FTP servers.
>
> I have a hunch. Will know better after hearing back from IBM.
>
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