If you login with a ".edu" or ".org" email address, you can create communities that restrict access to only people with the same email domain.

Tutorial on creating a community that only people at my university can access. First login with you university email. Then click title bar and create a new community. Name it, and mark the checkbox to restrict access to @your_university.edu - you can only restrict to your own email domain. Now, when people follow the link, they will be prompted to login with their university email

Common questions:

I logged in with a non-university email and created a community. Can I restrict that to my university?

No. You should logout, then login with you university email and create a new community.

What happens if I turn off the restriction?

Then anyone with the link can enter the community. But you can very easily turn back on the restriction.

What if I want people outside of my university to be able to enter?

You can temporarily turn off the domain restriction to let that person in. But note that increases risk of Nooks-bombing.