Postfix monitoring use cases

Each page starts from a question someone asks about a Postfix server, shows what Postfix logs for it, and the search, alert or check in Mailinois that answers it.

Question	Page
Why is this mail still in the queue?	Why is Postfix deferring mail?
Which addresses failed for good, and why?	Tracking Postfix bounces
Is there something better than grep and pflogsumm?	A Postfix log analyser that follows each message
Is our sending IP on a blocklist? Is our SPF right?	Blocklist and DNS monitoring for a mail server
A customer says the sign-in code never came. Did it?	Tracing app email through Postfix
We send for twenty clients. Can each see only theirs?	Many client sites on one Postfix relay

How to get the logs out of a particular setup (Debian or Ubuntu, Docker, mailcow, Kubernetes) is under setups. The quick start runs Mailinois locally with made-up traffic, if you’d rather click around first.