Postfix vs. outbound.protection.outlook.com

Microsoft has decided that checking senders hostname using HELO and rDNS is really 90’s, not really a rule and only for loosers and cowards: https://docs.microsoft.com/de-de/exchange/troubleshoot/antispam-and-protection/cannot-send-emails-to-external-recipients As an old school admin you have to tune your postfix to let the fluffy cloud mails from visionary early adopter outlook users. To solve the HELO part of the […]