Need a simple email diagnostic app

[dugr]

Hi all,
I'm looking for a program or script I can put on my remote users' desktops that will help us diagnose email issues.

Ideally the program would be able to:
Check for an internet connection.
Check if port 25 is being blocked by the access provider.
Ping my firewall.
Check if my smtp server is responding.
And pop up a message reporting any failure.

Thanks

Doug