FTP Connection times out after 127 files transferred

[John Robben]

Server: Redhat ES running ProFTP
Client: Windows 2000 Server command line ftp.

Client runs a script to initiate connection, set ASCII and mget *.

Transfer times out after 127 files.

Other clients are able to tranfer 127+ files no problem.

We're unable to duplicate this in testing.

Please help!

Thanks,

John

[Ivan Ferreira]

Use tcpdump or ethereal to capture the packets between these hosts to a file. Then analyze the file when the problem occurs. Probably you will have retransmitions and connections broken. Check switch port statistics and speed and duplex settings.

[Steven E. Protter]

Shalom John,

127 is not a magic number in the world of ftp.

I'd check and see if its not a restriction on windows.

Next, I'd see what the proftp configuration file looks like.

Are the files big? Do any of them take more than 15 minutes to download, maybe its a time based timeout after a long delay.

SEP

[John Robben]

We've been capturing all ftp traffic between our server and the client since the problem was reported. I enclose a sample (sanitized) as an attachment to this message. The sample begins after the last successful ftp. Times are since the beginning of the capture.

This is an isolated occurance, to this single customer. We have other customers that are doing this same thing without encountering issues.

All switch, duplex settings have been checked.

[Ivan Ferreira]

In this sample, it looks like a firewall is preventing ACTIVE ftp connections. Server sends SYN packets from ftp-data port, but client does not responds. Now, why this happens after 127 packets and not from the begginging? Have you tried passive ftp? (Windows ftp client does not supports passive ftp).

[rick jones]

The initial post says things stop after 127 files - then a later says after 127 packets.

If it is files I would wonder if perhaps the client isn't properly cleaning-up SOCKET handles and is hitting a Windows limit as someone else suggested. Particularly if other client FTP's (on the same Windows system?) can go beyond 127 files.

In FTP, each file transferred is a new FTP data connection - this is per the specification and cannot be changed.