If you can't get a definitive list, try a whitelist approach with a moderated queue for any domains not matching the whitelist. Once you see a domain that's an

If you can't get a definitive list, try a whitelist approach with a moderated queue for any domains not matching the whitelist. Once you see a domain that's an educational institute it gets whitelisted and further registrations from that domain get ok'd. No matter what text you include there, you're gonna get the odd student registering with a hotmail/gmail/yahoo account (I've tried something similar in the past). Try and get a list of free email accounts to give feedback on those straight away. I think any domain using the .edu TLD is safe straight-away, but I'm not from the US, so it may be worth clarifying that.