Its not possible to register white lists with the internal dnn registration module - but would be a relatively easy task for a custom registration module to achieve.

Alternatively - if its only a could of email domains - you could possibly alter the regex code that validates an email in the rego module - would need to have a think on that one ... the regex validator in dnn does checks to see if an email is of a valid form - altering the regex could do some limited tests of domains.

BUT - having said that - in reality - anyone can create a yahoo.com, gmail, hotmail email address . . . the list goes on forever almost which would pretty much mean you need to block out ever free mail provider - to keep anyone out.

Westa