Is it possible or feasible to have this configuration:

We have approximately 4000 users on our Windows Network environment
managed through AD.

We have a Sharepoint Team Services server running outside of our network
serving some of our employees plus outside partners (like an extranet).

Is it possible to have the AD users authomatically authenticated, and
simultaneously have non-AD users access the same shared sites if we put
this server on our network? Where would the credentials for the non AD
users be stored? On the Domain or the Sharepoint Team Services Server?

Any help would be appreciated.