I found the following: http://www.mxtoolbox.com/services_servermonitoring.aspx https://www.dnsstuff.com/products/mstc
Anybody have recommendations for these or other solutions?
5 years ago, most spam filtering was based on tech solutions (better Bayesians, DNS blacklists, RDNS ptr checks, SPF, etc.) Now it seems to be more "relationship" based.
First is to monitor your IP address rep by using the tools mentioned below. I also highly recommend SenderScore.org (run by ReturnPath, one of the big deliverability players).
Next step is to make sure you have the proper "feedback loops" setup with the large email providers. You can google how to set that up. This establishes a relationship between your IP and their servers -- e.g., with Gmail, a "report spam" click will get reported back to your email systems, so google knows you're trying to be good about removing unwanted recipients.
The last step is to use a deliverability expert. With something like mailchimp, you will see some of the tools, but you have to pay them to send your emails. If you want to send yourself, check out PivotalVeracity or Unica. They maintain accounts on almost all relevant email providers' systems, and they give you a seedlist that tells you how many emails got through, etc. They aren't cheap -- about $15-20k per year. But they let you run your email infrastructure and give you the necessary feedback about your email deliverability.
Our site has several other tools on it that you may find helpful including SMTP diagnostics to confirm your PTR and rDNS records and and MX Lookup tool as well.
Thanks again, @MxToolBox