Intermittent FTP Issue Help!

cousin_borat

Hello,

I've been handed the task of looking at an FTP issue my new company has recently developed. Basically it has been running fine for three years and now is intermittently hanging.

The command being used by the batch process is:
ftp -in *FTPADDRESS*

To start off I tried connecting interactively and see what happens there.
This is what happens when I connect using simple command
ftp *FTPADDRESS*
The FTP server we're connecting appears to be closing the connection but control is not passing back to the programme on our end which is why the FTP session appears hung to our programme. The only way to disconnect is to press control-c.

ftp> cd ARCHIVE
250 CWD command successful.
ftp> dir
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.

425 Can't open data connection.
421 Timeout (120 seconds): closing control connection.
ftp> dir
Not connected.
ftp>

ftp> cd PICK_RELEASE
250 CWD command successful.
ftp> dir
200 PORT command successful.
150 Opening ASCII mode data connection for /bin/ls.

421 Service not available, remote server has closed connection
421 Service not available, remote server has closed connection
ftp> dir
Not connected.
ftp>

All other FTP connections to other servers belonging to other partners are fine. The payload sent has not increased significantly, looking at the log files there is no difference in size between files successfully sent or ones that bomb out. Our server runs HPUX while the remote is Microsoft FTP. Any ideas or faced similar problems? For example is there a problem between these systems that prevents connections from disconnecting if there is a network problem??

Enda

fatherdougalmag

Have you tried another FTP server? Maybe an internal one? Or one on the same LAN?

cousin_borat

Thanks man. I'm not sure 100% which servers youre referring to. As mentioned our HPUX FTP server connects fine to various other client FTP servers. I think theyre mainly Linux.

I've asked this client whether a new firewall has been installed or have there been configuration changes.

By the way how doo you know whether an FTP connection is Active or Passive. Do you use FTP -d to watch out for Debug messages that tell you?

Sponge Bob

you should check whether its a passive vs active problem and that all ports are open ....or switch mode

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

cousin_borat

Ok, when I connect it is in Active mode.

This is from DOS FTP screen
250 CWD command successful.
ftp> dir
---> PORT 192,168,219,154,13,116

The IP address of the client machine is 192.168.219.154

The port is 3444 (16*256)+116

Now when I run Netstat on my machine it says

TCP AMS-N006118:3429 dezirw81.bertelsmann.de:ftp ESTABLISHED

Sponge Bob

tell the client to connect in PASV mode so

eg

open ftp.blah.yah pasv

cousin_borat

Thanks for the suggestion. Maybe it is that simple. However I want to recreate the problem first before changing any scripts.

Basically the FTP controls an interface between two systems Oracle and Medical Manufacturing system. XML documents generated by both systems are sent back and forth by both systems.

I'll have to talk to the Network Admins about the implicationis of using Passive over Active since I'm guessing the other company would have to make firewall changes to allow the incoming FTP packets on different ports from us.

cousin_borat

Is there a way of running the ftp command in debug mode and outputting to a log file.

Would like to do that and let it run until problem occurs again in production environment.