From: Plank, Jason (JPlank@concordefs.com)
Date: Wed Jun 21 2006 - 22:09:45 ART
Hm. Perhaps it depends on the setup. Yes the "control" ports both use is 21
but the data port for active is 20 and with passive it is random. See below:
http://slacksite.com/other/ftp.html <http://slacksite.com/other/ftp.html>
The following chart should help admins remember how each FTP mode works:
Active FTP :
command : client >1023 -> server 21
data : client >1023 <- server 20
Passive FTP :
command : client >1023 -> server 21
data : client >1023 -> server >1023
To catch "active" in an ACL, use ACL matching TCP "eq" FTP and FTP-DATA.
Passive is not the same.
Or you can reference RFC 959 - http://www.faqs.org/rfcs/rfc959.html
" PASSIVE (PASV)
This command requests the server-DTP to "listen" on a data
port (which is not its default data port) and to wait for a
connection rather than initiate one upon receipt of a
transfer command. The response to this command includes the
host and port address this server is listening on.
"
-------------------
J. Marshall Plank
Network Engineer
101 Bellevue Parkway
Wilmington, DE 19809
E-mail: JPlank@concordefs.com <mailto:JPlank@concordefs.com>
Phone: 302-793-5913
_____
From: Chris Lewis [mailto:chrlewiscsco@gmail.com]
Sent: Wednesday, June 21, 2006 9:00 PM
To: Plank, Jason
Cc: Ken; Cisco certification
Subject: Re: FTP connection type
Well, both passive and active use ports 20 and 21.
http://www.cisco.com/web/about/ac123/ac147/ac174/ac199/about_cisco_ipj_archi
ve_article09186a00800c85a7.html
<http://www.cisco.com/web/about/ac123/ac147/ac174/ac199/about_cisco_ipj_arch
ive_article09186a00800c85a7.html>
Provides a full description.
Chris
On 6/21/06, Plank, Jason <JPlank@concordefs.com
<mailto:JPlank@concordefs.com> > wrote:
It means ACTIVE FTP, which uses TCP ports 20/21.
-------------------
J. Marshall Plank
Network Engineer
101 Bellevue Parkway
Wilmington, DE 19809
E-mail: JPlank@concordefs.com <mailto:JPlank@concordefs.com>
Phone: 302-793-5913
-----Original Message-----
From: nobody@groupstudy.com <mailto:nobody@groupstudy.com>
[mailto:nobody@groupstudy.com <mailto:nobody@groupstudy.com> ] On Behalf Of
Ken
Sent: Wednesday, June 21, 2006 6:11 PM
To: Cisco certification
Subject: FTP connection type
Hello,
When there is a statement, "suppose that this FTP server does not
support PASV FTP connection", what kind of difference does it make
in the ACL configuration?
I am referring to the QoS question 8.3 in Lab 2 of IE work book.
Thanks,
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