snddst activity

[<franz400@xxxxxxxxxxxx>]

How do I monitor that snddst mail is actually successful?
This is an existing app sending mail, but operations doesn't know of a problem till users complain of missing emails a day or so later.
All mail is forwarded to an exchange server offsite. 
Network management is mostly outsourced and they make changes on their own that have affected us. 
This is a V4R5 system
Have ended smtp server and reset msf many times, but don't see how to find what is waiting to go, or what failed to forward.
jim franz