On Tuesday, 03/13/2007 at 04:24 AST, Neil Carson <[EMAIL PROTECTED]> 
wrote:
> Please see the below explanation from our ISP ....
> What I am trying to do is change the default listen port (ftp) of 21 to 
a four 
> digit port number.

Put "PORT xxxx" in the SRVRFTP CONFIG file on TCPMAINT 198.

> When our ISP opens the firewall xxxx I can connect using the new port 
(via my 
> client) but I cannot get a filelist via the client (outside of the 
firewall)
> Does their explanation make sense ? Is there anything I can do since we 
are 
> using z/vm 3.1 to resolve the filelist problem.

Their explanation does make sense, yes, but z/VM 3.1 doesn't have passive 
FTP support.  With passive FTP, the server will tell the client what port 
number to connect to for data transfer (e.g. file list).  The firewall 
watches for that disclosure and it opens up the indicated port.

FYI, z/VM 5.3 adds a PassivePortRange statement to enable you to open up a 
pre-arranged hole in the firewall, allowing passive FTP to work even when 
the control connection is encrypted.

Alan Altmark
z/VM Development
IBM Endicott

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