We are looking to build a new website that is specifically for commercial/business use. We need to only allow 'business' email addresses register. So users with Gmail, Hotmail, Yahoo etc cannot apply with those email addresses.
Is there a way to do this, other than creating a blacklist of domains such as gmail.com, hotmail.com etc? It will be an international site - so it will be impossible to blacklist all of the public email providers.
Thanks Ian
As others have stated, it doesn't really make much sense to try to detect a business customer based on his email domain, but if you really wanna go down that road, blacklisting is your best bet. The spamassassin freemail plugin provides a good default blacklist:
http://svn.apache.org/repos/asf/spamassassin/trunk/rules/20_freemail_domains.cf
Small businesses are having @gmail.com addresses (and some people are not able to configure their gmail to redirect emitting email address to something else).
Some big businesses may have internal policies disallowing such subscriptions with the company email, so some people there would also use a @gmail.com address for that.
So I would not filter out such email addresses.
Private individuals occasionally run their own email servers as well. Consider:
a) Person (A) registers a domain from a registrar like gandi.net, and signs up for their email service and hosted blog.
b) Company (B) registers a domain from the same registrar and signs up for their email service.
There is no way for you to differentiate, technically, between these two. They will even share the same mail server [which can serve multiple domains].
There are some online services which do provide these services (Email Verifications).
Take a look here:
Their API Documentation: https://emailhunter.co/api/docs#email-verification
