I am totally new to MIAB, have been using iRedMail in the past few years. Wanted to ask if someone can guide me in the right direction - I am looking for information about deployment where MIAB is not directly exposed to the internet and located behind another firewall. Are there any FAQs or blog posts providing information about the best practices for this type of installation.
I am trying to understand at the moment why I would need to run public DNS and firewall on the mail server when all of these is properly handled by the existing parts of the network? I use Cloudflare DNS which points to the right hosts and CNAME records and pFsense firewall which filters and forwards traffic to the right internal servers.
Simple question - MIAB makes sense only when you have public IP addresses directly assigned to it and the host faces public internet or it can be efficiently used in a ‘behind firewall’ scenario?