Little FTP problem

Sometimes I ftp directly from my firewall : it works right.
I have problems when I try to download very large files
(for example 15-20 Meg), when I try to download one of these
files my ftp-client lock-up after the download it's complte.
The file is downloaded correctly,but I cannot download multiple files(for example with mget), my ftp-client locks-up when the first download it's complete, this happens
only with very large files.
I have tried with the standard command-line ftp of linux
Redhat 6.1 and with ncftp, it happens the same.
I hope someone can help me!
Thanks in advance
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jlevieConnect With a Mentor Commented:
The problem occurs as a result of the way the FTP protocol works. An FTP client opens its connection on port 21 and uses that port for commands, but uses port 20 for data transfers. when a large file transfer occurs that takes longer than the connection timeout in the firewall, the original connection on port 21 is dropped since there won't be any activity on port 21 during the transfer. Thus when the transfer completes you no longer have an open command connection.

Some firewalls (Cisco Pix with 4.x & later) can implement a fix for the problem in the firewall. Basically the port 21 connection held open as long as data is flowing using port 21, even though there's no traffic on port 21. Using PASSIV mode should also work around the problem.
Is the FTP server a machine of yours or is it elsewhere on the Internet?

Are you running as root or a non-priv user?  Is disk quota a potential problem?

Do you have this experience with many FTP servers, or just one in particular?

How much memory and swap space to you have?  

Please tell me about your connection to the Internet.  Are you using a dialup?   Is this simply a case of a third-rate ISP (AOL, etc.) that can't keep your connection active?

When your ftp client freezes, are you still connected to the Internet?

Longshot:  I have seen cases where someone sets up a firewall (on the FTP server side), that implements it's own limitation on the maximum size of a file transfer.  When that limit is reached, the firewall drops your connection.  This is rather foolish, because the client software has no idea what happened, and the most likely action from the end user is to retry the file transfer, which will surely fail again for the same reason.  
shea75Author Commented:
I have tried with PASV mode but it happens the same
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Okay, there's a way to work around the problem. One of the other utilities included in the ncftp distribution is "ncftpget", which is intended for scripting use (see "man ncftpget"). You can use it to in a script file (one ncftpget per file) to retrieve multiple files.
shea75Author Commented:
I do not have this utility installed on my system.Where I can get it?
Fixed the -1 problem on this question.
Escrow points corrected.

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