["Heyligen Tom" <Tom.Heyligen@xxxxxxxxxxx>]

Fonte,

If you're using a command line client like NcFTP or the embedded one from your OS, there are no additional data connections (dir listing) at all.

Probably your graphical client has an option somewhere in the Preferences menu? Disable options like "Display server content on connect" etc...

Best regards,
 Tom.


-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx [mailto:ethereal-users-bounces@xxxxxxxxxxxx]On Behalf Of fonte fonte
Sent: woensdag 8 maart 2006 16:28
To: Ethereal user support
Subject: RE: [Ethereal-users] 3 TCP Connections Instead of 2


Hi Tom

Thanks a lot for the info! 

Is there anyway I can avoid this extra data connection and have only one data connection throughout the download? I don't know what I've done in the past when I managed to have only 1 data connection per download. Reason is I want to calculate total data throughput per download and by having 2 data connections, I'm not sure whether I should add up both throughputs or ignore the first connection (request of directory listing).  It's only a few packets with few bytes.

Thanks


Heyligen Tom <Tom.Heyligen@xxxxxxxxxxx> wrote:
Fonte,

Whenever a FTP client requests a directory listing, this creates a new TCP connection. This connection is commonly referred to as a data connection, although the "data" it contains is a list of files/directories. This explains why you noticed ASCII mode and the "ls" (dir) command.

By default, graphical FTP clients like FileZilla automatically request a server directory listing for you, hence explaining a data connection even when not up/downloading any "real" files yet.

Hope this answers your question.

Best regards,
Tom Heyligen.



-----Original Message-----
From: ethereal-users-bounces@xxxxxxxxxxxx [mailto:ethereal-users-bounces@xxxxxxxxxxxx]On Behalf Of fonte fonte
Sent: woensdag 8 maart 2006 11:41
To: ethereal-users@xxxxxxxxxxxx
Subject: [Ethereal-users] 3 TCP Connections Instead of 2


Hi list

Another question from me. Why do I see 3 TCP (1 control and 2 data) connections for my FTP download instead of the usual 2 connections (1 control and 1 data)?

This is what I usually get from my captures:

On control connection (port 21):
Login to server
Access file folder
Request for file download etc

The last command I get before data connection takes over is 'FTP response 150 opening binary mode data connection for ftp_sco_com.tar'. Then right after that on data connection (port 20), the download begins after handshake.

So I only have 2 TCP connections.

However, of late, there's always an extra data connection created everytime I did the download.

On control connection everything was fine, however, I noticed that the last command I got before the first data connection took over was 'FTP response 150 opening ASCII mode for /bin/ls'. Then the first data connection took o ver, managed to send 56 bytes of data then immediately sent a FIN (and ACK,FIN by client). The content of data was the file name ftp_sco_com.tar.

After this happened, control connection continued to request for the file download and I finally got the 'FTP response 150 opening binary mode data connection for ftp_sco_com.tar'. The second data connection took over and the download beg un as normal (on different client port).

So I have 3 TCP connections.

I don't have a clue why the extra data connection was created, and why it was on ASCII mode etc. To me, this data connection was a little bit 'premature', it seemed to be interrupting the process.

Hope anyone can give any ideas. By the way I set the transfer type to Auto in FileZilla.

Thanks
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