> Postfix can easily be configured to reject incoming emails from senders without a reverse DNS mapping for their IP address, which makes it reject a lot of spa

> Postfix can easily be configured to reject incoming emails from senders without a reverse DNS mapping for their IP address, which makes it reject a lot of spam Historically some corporate domains ignore that rule (yea, in 2025!), so I would advise not to reject any email and run everything through spam analysis daemon. This way you won't lose any email at expense of elevated load on your server