Date: Tue, 29 Apr 1997 11:23:14 +0100 From: Damian Hamill <damian@cablenet.net> To: "David H. Brierley" <dave@galaxia.com> Cc: freebsd-isp@freebsd.org Subject: Re: SMTP gateway clients Message-ID: <3365CC12.695678E2@cablenet.net> References: <Pine.BSF.3.95.970428141252.2711A-100000@terminus>
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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
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