Should I modify the A record and reverse DNS to point to the Public IP on the Cisco Spam Blocker
Its important that you have A & PTR records set correctly. Failure to have correct reverse dns is a major problem for many senders of mail.
There are some good guidelines on the internet around other best practices that are worth reading, including:
- MAAWG - sender best practice
Not all may be relevant however its an excellent source of things to consider for sending mail to the internet
- Gmail POstmaster