On Sat, 19 Sep 2009, Martin Allan Jensen wrote: > The company I work for have approximately nine mail servers, including > Postfix, qmail, sendmail and exim. They would like to make ONE SMTP > relay host server so that all their customers can use their SMTP > server to send mail through. The customers already get their incoming > mail through their mail servers. > > I fail to see a way to make this possible without creating an entirely > open relay, or creating a database with usernames and passwords and > use SASL. Does anybody know if it is possible to make the SMTP host > contact the mail server and verify that the sender email exists on > their incoming mail server? Or is there another setup recommended?
You must setup SASL and only let authenticated users relay through this new server. Forget about contacting the other mail servers to verify that the sender email exists; that is in no way a form of authentication. > Looking forward to hear from you, a link, or even some rough notes > would be nice. http://www.postfix.org/SASL_README.html -- Sahil Tandon <sa...@tandon.net>
