I have to admit I am a spool watcher. I routinely take a look throughout the day as it gives me a quick glance at possible issues such as email domains not accepting email or not functioning, possible spam compromises, blacklisting, etc.
Usually there are about 100+ emails in the spool trying their 10 times to send - they are usually all System Admins sending NDRs to spammers since the Exchange server they tried to send down to are using Content Filter, or they are just plain User Does Not Exist notices from Exchange since some clients use us as a incoming gateway.
Is there a way to tell the SM Incoming Gateways to not send Smartermail NDRs? Example; here is what our current spool has 213 of:
From: "System Administrator"
Date: Tue, 14 Jun 2016 15:24:38 -0400
Subject: Delivery Failure