As Microsoft is constantly behaving as a bad player, I need to use a free commercial relay. The free tier is limited in volume so each customer need his own Relayhost User/Relayhost Password set in "Mail Domain". So far so good. Now I have these customers who are going over the free tier, would it be possible to only route the Microsoft's domains through the relay with a transport to save some volume? So sending all non-Microsoft's emails with Postfix and only use the relay for Microsoft's one. It might be possible somehow messing with Postfix's config files but I'm wondering if it's possible to set it up within the customer's panel. I've skimmed most of the forum but I can't find any solution. Any help would be greatly appreciated.
You do not say what kind of setup you are using. As you post in the forum section for non-ISPCongig systems, I can only assume it's not ISPConfig.
Why do you need a relay in the first place? Can't you use postfix? As long as emails you are sending - are dkim signed - the domains have a dmarc and spf record (besides of course dkim) - your postfix has a valid certificate for tls - the ip your postfix is sending from has a reverse dns record set to your postfix's hostname you should be good to go with the need of a relay and Microsoft wouldn't have any reason to complain.
They do not complain, they just forget to deliver the mail when they not refuse it for being in a bad block. My server is 110% compliant, it's just they carpet bomb full IPs ranges, and all their Postmaster tools are plainly useless. I'm not the only one complaining about their lack of care, but I'm too old and too poor to sue them, so I need a relay.
been there. done that.. microsoft blocked an entire ASN of aws ip's, one of which was my mailserver. for months.. and then when they finally unblocked the ASN.. they still blocked my ip and refused to accept mail from my mailserver.. claiming they were receiving too much spam mail from that ip over the last couple of months.. a blatant lie. when i pointed out that was impossible because they weren't even allowing that ip to connect to their own mailservers that entire time.. and my mailserver, was, instead, relaying EVERYTHING through a digital ocean droplet, they quietly unblocked my mailserver's ip. no apology for lying, or for abusing their position.. i'm also, now, blocking thousands of microsoft azure ip's from connecting to my webservers, because of vps's they're hosting on those ip's which are continually trying to hack our hosted websites.. they won't sort out their own problems, but continually accuse others and unfairly block them.. and they wonder why that have such a bad reputation.
From within ISPConfig, you can set up relaying per sender domain but not by recipient domain or recipient and sender domain combined. So, you will have to configure that manually if you want only emails to MS services routed through a different relay.
Thank you Till. It's what I thought, I wanted confirmation. And I guess you do not plan to implement this feature.
I don't plan to implement this at the moment. Have you considered the strategy that @nhybgtvfr described to use a cheap cloud server at anther provider for relaying instead of using a relay service?
