asp.net - implement form authentication on some pages not all pages -

i want implement form authentication on pages not pages.

in application many other pages there want make public contact us, , all.

for pages want implement form authentication.

please me on this.

<authorization>   <deny users ="?" />   <allow users = "*" /> </authorization> 

if had directory called "administration" contained administration pages, add following web.config:

<location path="administration">     <system.web>       <authorization>         <allow roles="admin" />         <deny users="*" />       </authorization>     </system.web>   </location> 

then users in role "admin" can access pages in "administration" directory. path can substituted specific page rather directory if required.