Dnia 11.10.2020 o godz. 19:03:29 Anthony Ananich pisze: > > I'm trying to use single postfix instance for serving several domains. So > let's say postfix hostname is mail1.hostmaster.com > <http://mail1.hostmaster.com/> and it is used to send messages on behalf > of client1.com <http://client1.com/> and client2.com > <http://client2.com/>. > > The issue is that these messages are identified by SPAM filters as > untrusted. Most of them expect hostname to match served domain name. In > case Postfix send each domain's outgoing messages from unique IP and this > IP is whitelisted using DNS, it seems to make no difference. > > I wonder if there is a way to make postfix to use custom smtp banner > (helo) based on IP address it is sending message from?
That's a bad idea, as what most spam filters actually do expect is that hostname advertised in HELO matches the actual DNS hostname of the sending host. Also the forward and reverse DNS should match. "Forging" the HELO hostname will only count more, and not less, towards your message being classified as spam. Your sending server should be either explicitly listed as trusted source in SPF record for domains client1.com, client2.com etc. or at least be a MX for these domains if there is no SPF record. That should satisfy most reasonable spam filters. -- Regards, Jaroslaw Rafa r...@rafa.eu.org -- "In a million years, when kids go to school, they're gonna know: once there was a Hushpuppy, and she lived with her daddy in the Bathtub."
