From: Mas Kato (tealp729@xxxxxxxx)
Date: Thu May 10 2001 - 21:29:36 GMT-3
Thanks... Sorry about that. I got it mixed up with the source port the
server uses for the data channel during an active session.
Mas
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Wayne Gustavus
Sent: Thursday, May 10, 2001 9:17 AM
To: 'Mas Kato'; 'Shane Miles'; ccielab@groupstudy.com
Subject: RE: Access-list question
One minor correction on the passive-mode FTP. One would think that the
FTP
client would initiate the data transfer connection to the server with a
source port of 20 (or keyword ftp-data). However, this is NOT the case.
In
passive mode FTP, the client simply chooses the next avail port >1023 as
its
source port and uses the destination port it received from the FTP
server as
the destination port.
Skeptics can check out the IPJ article by Tom Thomas here
http://www.cisco.com/warp/customer/759/ipj_2-3/ipj_2-3_oneb.html ,
or TCP/IP Illustrated Vol 1, or better yet, a quick sniffer trace!
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