Classic asp ans asp.net user Authentication.

I have a classic asp page , where user enters username and password:
i authenticate the user on the classic asp page and if the user is authorize i redirect the user to the Asp.net website i have built.(eg. http://123.17.162/Main.aspx ).
even if the user copy paste the above link it works. i want to make a way that it should not work if the user uses that link ,it should only work when user is authorized form classic asp page.
i also want to make a logout page in my asp.net website.


Any help would be appreciated

Regards






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