Re: ftp problem

[Scott Klement <klemscot@xxxxxxxxxxxx>]

Did you upgrade the server's software when you did this?   Change OS
versions, or FTP software?  Or, change your router/firewall in some way?

Each file transferred via FTP opens a new connection on a new port.   The
FTP client sends the PORT command to the FTP server to tell the server
how to connect to the client so that it can open this new connection.
The fact that you never see a 150 message means that it's unable to
establish the connection that the client/server have agreed upon.

The client will typically choose a new/available port for every single
connection, letting the TCP/IP stack choose which port is available, and
then will send the new port number.

>From the symptoms you list, I would assume that some of the possible ports
are being blocked by a firewall or NAT.   It's possible if you changed
either the OS or the FTP software that the "range" of ports that FTP uses
has changed.  If that's the case, it would explain why the upgrade would
change the behavior.

The easiest thing to try (which may or may not help) would be using
passive mode for your FTP.   Simply specify passive in your batch file,
and see if that helps.

The thing that really puzzles me is the need to stop/start the FTP server.
The whole idea that the FTP server stops working and needs to be
started/stopped just because of a network error is not a good sign.
That's a bug that should be reported to IBM.  I'm sure that IBM wants
their server to be as stable as possible!


On Tue, 29 Jul 2003, Jim Franz wrote:
>
> At V4R5 I have a site I FTP to from an offsite pc, using a batch file &
> WinXP, every week, 2 diff files.
> Working for years. After a "network upgrade", the FTP is sometimes
> "hanging" and won't work till i stop/start the FTP server. (have latest cume)
> ftp logs on
> 200 PORT subcommand successful    and hangs there...
>          never get 150 Sending file......
>
> I can see FTP job QTFTPxxxxx and nothing odd in log.
> In exit program log i can see the SET and GET, just like successful one
>
> Happens about 1 out of 4 tries, but once happens, must reset FTP server.
> Any ideas?
> jim franz
>