From owner-freebsd-isp Tue Apr 29 03:25:58 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.5/8.8.5) id DAA09263 for isp-outgoing; Tue, 29 Apr 1997 03:25:58 -0700 (PDT) Received: from axe.cablenet.net (axe.cablenet.net [194.154.36.65]) by hub.freebsd.org (8.8.5/8.8.5) with SMTP id DAA09258 for ; Tue, 29 Apr 1997 03:25:55 -0700 (PDT) Received: from axe (localhost [127.0.0.1]) by axe.cablenet.net (8.6.9/8.6.9) with SMTP id LAA15143; Tue, 29 Apr 1997 11:23:15 +0100 Message-ID: <3365CC12.695678E2@cablenet.net> Date: Tue, 29 Apr 1997 11:23:14 +0100 From: Damian Hamill Organization: CableNet Ltd X-Mailer: Mozilla 3.0 (X11; I; SunOS 4.1.4 sun4m) MIME-Version: 1.0 To: "David H. Brierley" CC: freebsd-isp@freebsd.org Subject: Re: SMTP gateway clients References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-isp@freebsd.org X-Loop: FreeBSD.org Precedence: bulk David H. Brierley wrote: > > > > It's called ETRN. > > > telnet to port 25 and enter the command > > > > > > ETRN domain.name > > > QUIT > > > > but it only works with a fixed IP address for the relay. The original > > question was how to use dynamic IP address for the relay. > > What I did was to write a short program that would modify the > sendmail configuration files to reflect the "current" IP address > for the domain. Create a special login/password combination which > runs the program, have the program prompt for a domain name and a > second password, query the system to find the IP address of the > incoming connection, rewrite the files. When the customer then > connects a few seconds later and gives the "ETRN" comand it will > deliver the mail just fine. The biggest problem is making sure > that the host at IP address x.y.z.z is still the same host 5 minutes > later, otherwise you end up delivering the mail to the wrong machine. > This is probably best handled by having the original program maintain > some form of connection to the customers machine and reset the > sendmail configuration files when the connection drops. > > Before anybody asks, I no longer work for the ISP that I did all > of this for so I no longer have access to the code. On the other > hand, if anybody wants to hire me to come up with a solution for > them I am available at reasonable rates. Or you can buy our ready made solution that has been working fine for the last two years. http://www.cablenet.net/cablenet/popinabox/license.html We have a number of components which work together to solve this problem; a dynamic DNS server. a special version of sendmail, tailored for dynamic IP. a process which moves email to user specific queues. regards damian -- * PIAB - PoP In A Box - the total solution for ISPs, with more features * than a Constable landscape, and very cheap too!! * http://www.cablenet.net/cablenet/popinabox/ * Damian Hamill damian@cablenet.net