Hi Ron,

Try this:

https://www.dns-oarc.net/oarc/services/dnsentropy

My take on it is that if you get "Great" as a rating you are not as vulnerable as you might be. Anything else and you certainly have problems.

Also the vulnerability checker link on this site (needs Java?)

http://www.dnsstuff.com/

And Steve Gibson?

https://www.grc.com/dns/dns.htm