Subject: Passive FTP & Web browsers

From: "Pavel P. Zabortsev" <[email-masked]>
Date: Thu, 4 Feb 1999 09:56:06 +0300

Hi.

Is there any way to disable PASSIVE command on wu-ftpd?

This is because our FTP-server is behind Firewall, which forbids passive
mode for ftp by packets filtrations. Web browsers use passive mode for
access to FTP-servers (correct me, if I mistaken). The result is
impossibility to access this FTP-server!

Yours sincerely,
Pavel

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Pavel P. Zabortsev        e-mail: [email-masked], [email-masked]
Software engineer          voice: 220-4350, 220-4513, 22-87
CDO UPS of Russia            fax: 220-6542
Moscow, Russia               ICQ: 15371542
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From: Gregory A Lundberg <[email-masked]>
Date: Thu, 4 Feb 1999 07:55:53 -0500 (EST)

On Thu, 4 Feb 1999, Pavel P. Zabortsev wrote:

> This is because our FTP-server is behind Firewall, which forbids
> passive mode for ftp by packets filtrations. Web browsers use passive
> mode for access to FTP-servers (correct me, if I mistaken). The result
> is impossibility to access this FTP-server!

The current VR version has this feature, as does the current BeroFTPD
version (I believe).  Both are available at my ftp site:
  ftp://ftp.vr.net/pub/wu-ftpd/

-- 

Gregory A Lundberg		Senior Partner, VRnet Company
1441 Elmdale Drive              [email-masked]
Kettering, OH 45409-1615 USA    1-800-809-2195

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From: Gregory A Lundberg <[email-masked]>
Date: Thu, 11 Feb 1999 08:15:58 -0500 (EST)

On Wed, 10 Feb 1999, Dave Wreski wrote:

> I thought passive mode was the preferred way of doing FTP data transfers?  This
> is because the server designates the port that will be used, instead of allowing
> the client to request the data port, no?

> Why wouldn't you let this thru your firewall?

Maybe you are only doing FTP for specific customers who are required to
use PORT mode?  Whatever the reason, it's the local netadmin's rule.

Yes, the VR version has a compile-time option to disable either PASV or
PORT (won't let you do away with both).  Dunno if Bernards folded that
change into BeroFTPD yet.

--

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From: Bret McDanel <[email-masked]>
Date: Thu, 11 Feb 1999 10:48:56 -0500

---Reply on mail from Dave Wreski about Passive FTP & Web browsers

> Why wouldn't you let this thru your firewall?
well as I understand things the ftp server will send from port 21 (or
rather by default ftp port +1 unless manually configured differently)..  
This means that its easy to configure filters, however depending on the
level of the firewall depends on how hard that filter is to get around..

As for disabling PASSIVE mode, yes its possible, however it will break
stuff if you do (ie netscape/explorer will only connect via PASV AFAIK,
and a lot of people are using that (something like 40% of all data
connections to microsofts ftp site are PASSIVE (and for those that will
complain about me saying that site, this is public info so it doesnt
matter), do you want to deal with 40% (or whatever it is for you) of 
people complaining that they cant get files???)

To disable PASSIVE you will have to disable the PASV command, which isnt
that hard but AFAIK requires a code change..

-- 
Bret McDanel                                    http://www.rehost.com
Realistic Technologies, Inc.                             973-514-1144

     These opinions are mine, and may not be the same as my employer

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From: Dave Wreski <[email-masked]>
Date: Wed, 10 Feb 1999 21:26:21 -0500 (EST)

Thanks,
Dave