From owner-freebsd-questions Sat Feb 19 18: 5:31 2000 Delivered-To: freebsd-questions@freebsd.org Received: from if.scientech.com (eaglerock.if.scientech.com [198.60.85.3]) by hub.freebsd.org (Postfix) with ESMTP id C665337BD93 for ; Sat, 19 Feb 2000 18:05:28 -0800 (PST) (envelope-from cmott@scientech.com) Received: from if.scientech.com (IDENT:cmott@if.scientech.com [10.128.1.6] (may be forged)) by if.scientech.com (8.9.3/8.9.3) with ESMTP id TAA28286 for ; Sat, 19 Feb 2000 19:05:27 -0700 Date: Sat, 19 Feb 2000 19:05:27 -0700 (MST) From: Charles Mott To: questions@FreeBSD.ORG Subject: Re: Redirecting/mapping ports to a local machine... help! In-Reply-To: <20000219203204.G60348@cc942873-a.ewndsr1.nj.home.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-questions@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 19 Feb 2000, Crist J. Clark wrote: > This is a server issue not a client issue. An ftp client can do > passive ftp from behind a NAT box. However, active ftp would not > work. This is not correct. There is specific code in the packet aliasing library used by natd for handling "active" (i.e. non-passive) connections. Essentially, the packet aliasing code looks for a PORT command in the control stream and then sets up a back-channel to wait for the port 20 control connection from the ftp server. Many people use ftp in non-passive mode from behind natd without any problems. > > Use of a control channel and a data channel is a basic part of the ftp > protocol. See RFC 959. Unimplemented RFC 2428 might be interesting too. > -- > Crist J. Clark cjclark@home.com > > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-questions" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message