MXToolbox.com
This test will list MX records for a domain in priority order. The MX lookup is done directly against the domain's
authoritative name server, so changes to MX Records should show up instantly.
http://www.mxtoolbox.com/
Outlook.com Postmaster Services
Microsoft provides information to information technology professionals who administer systems that send email to and receive email from Outlook.com. It also provides some information about how users with Outlook.com accounts can report junk email and phishing attempts.
https://sendersupport.olc.protection.outlook.com/pm/
SenderScore (by ReturnPath)
With Sender Score reputation data, you’ll know right away what ISPs and other email receivers
think of your email program – and how your program stacks up against everyone else’s. Also,
you’ll be able to see exactly what you need to change to improve your email reputation and
subsequent email delivery rates.
http://www.senderscore.org/
"There are hundreds of bounce formats you can encounter
on the Net, and the fact that new or obscure bounces
can be caught simply and painlessly with BounceStudio
saves us valuable development time."
