RE: FTP Questions

What I had a problem with is during large transfers the FTP control on
port 21 times out and disconnects thus stopping the transfer.

Christopher Bipes
Information Services Director
CrossCheck, Inc.


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Scott Klement
Sent: Thursday, February 01, 2007 9:58 AM
To: Midrange Systems Technical Discussion
Subject: Re: FTP Questions

The ftp stops at a certain record and disconnects and the file we 
receive is the same every time we try to get it with the same record 
count.

So you're receiving part of the file, but not all of it?  Is that
correct? 

From the log you posted, I would've assumed that you didn't receive

anything, because that's the most common problem with FTP.  But, in
reality, you're receiving part of the file.  If that's the case, you can
rule out a bunch of things:

a) It's not a firewall issue.
b) It has nothing to do with passive vs. standard FTP mode.
c) It has nothing to do with permissions.

The error message in your log says this: "Unable to receive data from 
TCP/IP.".   This means that something went wrong during communications.
I 
don't see how that could possibly be bad data in the file!  FTP doesn't
care what data is in the file...  The fact that downloading this file
works just fine from a PC makes it clear that the contents of the file
aren't the problem.  (Unless the FTP client is giving you incorrect
error messages, of course!)

Perhaps there's a bug in the TCP/IP stack in i5/OS.  Or perhaps ICMP is
blocked by a firewall... I've had that problem where someone blocked
ICMP and that caused my FTP transfers from i5/OS to get disconnect
errors. 
Solved the problem by using a FreeBSD FTP proxy.