pmg-administration.adoc: descrive delivery status

pmg-administration.adoc

@@ -119,6 +119,32 @@ specific text in the logs ('Filter' entry).
 
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+The 'Status' field summarize what happens with an email. {pmg} is a
+mail proxy, meaning that the proxy receives mails from outside,
+process it and finally sends the result to the receiver.
+
+The first phase is receiving the mail. The proxy may reject the mail
+early, or instead accepts the mail and feeds it into the filter. The filter
+rules can block or accept the mail.
+
+In the second phase, accepted mails need to be delivered to the
+receiver, and this action may also fail or succeed. The status
+combines the result from the first and second phase:
+
+[options="header",cols="2s,1d,5d"]
+|====
+|Status |Phase |Description
+|rejected             |1 | Email rejected (e.g. sender IP is listed on a IP blacklist)
+|greylisted           |1 | Email temporarily rejected by greylisting
+|queued/deferred      |1 | Internal Email was queued, still trying to deliver
+|queued/bounced       |1 | Internal Email was queued but not accepted by the target email server (e. g. user unknown)
+|quarantine           |1 | Email was moved to quanantine
+|blocked              |1 | Email was blocked by filter rules
+|accepted/deferred    |2 | Email accepted, still trying to deliver
+|accepted/bounced     |2 | Email accepted but not accepted by the target email server (e. g. user unknown)
+|accepted/delivered   |2 | Email accepted and deliverd
+|====
+
 
 Postfix Queue Administration
 ----------------------------