RE: Odd Data Transfer Issue

["John Fox" <foxj@xxxxxxxxxxxxx>]

FTP communications uses 2 ports.  The command port (port 21) is used to
send the FTP commands from the client to the server.  The data port is
opened between the client and the server when there is a need to
transfer data between the two systems.  This is port 20 if you are using
Active connection or it could be a port number greater than port 1023 if
you are using passive mode.  This web page does a descent job of
explaining things:

http://www.slacksite.com/other/ftp.html

The error message you sent seems to indicate that a connection for the
data port could not be established in order to transfer the data.

This kind of problem typically happens if there is a firewall between
the 2 servers that is not properly configured, or there is a change to
the FTP server and one is expecting PASV while the other is expecting
Active connections.

I recommend that you troubleshoot along these lines for a correction to
your problem.

-----Original Message-----
From: ftpapi-bounces@xxxxxxxxxxxxxxxxxxxxxx
[mailto:ftpapi-bounces@xxxxxxxxxxxxxxxxxxxxxx] On Behalf Of Brian
Sent: Thursday, June 05, 2014 1:57 PM
To: HTTPAPI and FTPAPI Projects
Subject: Odd Data Transfer Issue

Hello List,

We've suddenly begun to experience an issue moving files between our
iSeries and another one.  I do not believe this is an FTPAPI issue at
all because we are using it to move files to and from our machine and
other iSeries without issue.  I am just hoping someone may have ideas on
how to locate the root cause of this or get more info from FTPAPI.

We are using put/get/append at different times to move iSeries database
files around between our iSeries and another.  We are using binary mode
*ON and trim mode *OFF.  This had been working just fine a week ago and
suddenly this week we are getting the error message in FTPAPI of "Not
able to open data connection.". We are not getting error on the same
file each time and not every time we connect and move files around.

I know this is pretty vague but I am hoping someone may have some
insight or thoughts on this.

Thanks much in advance.


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