ISO service which will return a mail domain as valid or not.

You send an email and you get a
Reason: 5.1.2 - Bad destination host ('000', ['DNS Hard Error looking up
aasdfdfsdf9788asfdsf8d87f8d.com (MX): NXDomain'])

You decide to get proactive and scrub a file containing all these
destination addresses. You want to run something like
select customer_number, customer_name, email_address,
email_domain_valid(email_address)
from customer_master
where email_domain_valid(email_address) = '0'

Does anyone have something like the desired email_domain_valid?

I can worry about the performance later (like grouping by domain names, a
list of whitelisted domain names, etc) So let's not chase that squirrel.