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Date:      Mon, 3 Apr 2000 10:15:51 -0600 (MDT)
From:      Paul Hart <hart@iserver.com>
To:        Michael McHugh <mchugh@actv.com>
Cc:        freebsd-security@FreeBSD.ORG
Subject:   Re: Firewall rules for an internet FTP server?
Message-ID:  <Pine.BSF.4.21.0004031009530.13866-100000@anchovy.orem.iserver.com>
In-Reply-To: <38E8A393.D492BB3B@actv.com>

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On Mon, 3 Apr 2000, Michael McHugh wrote:

> Also, ftp can be run in two modes - passive and active.  Passive
> involves pure port 21, active involves the ftp server opening a
> connection from port 20 to a high numbered port on the client.

Uhh, not quite.  Passive mode DOES involve the client connecting to a high
numbered port on the server (chosen by the server).  Both active and
passive modes require a separate data channel and are troublesome to
firewall.  The difference is only in who picks the ports and who contacts
who.

Paul Hart

--
Paul Robert Hart        ><8>  ><8>  ><8>        Verio Web Hosting, Inc.
hart@iserver.com        ><8>  ><8>  ><8>        http://www.iserver.com/



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