Mixing Form and Windows Authentication

[Rob]

I am currently making the move from ASP to ASP.Net and I have hit my
first stumbling block…
Currently I server users from both inside my Domain and Outside of the
Domain…
What I do now …
Check for a particular Session Variable if the variable has not been
set based on the incoming IP address I do a redirect to one of two asp
pages… one for Internal Users and one for External Users

For the Internal User I get their domain user id via the server
variable Logon_User and then by way of ADSI check their membership in
a Domain Group … if all is good set the session variable and they go
on else send them to a not authorized page…

For the External User I send them to a "Form Based" logon and check
them in a SQL Database

Will I still be able to do this in ASP.Net … not sure how the
authentication mode works Windows vs Form and can I use both methods
for authentication and is it possible for a WebService to handle the
Authentication?

Thanks