How do you protect Web Services when using it as JSON via Jquery?

Question

I currently use asmx for Json transactions using Jquery.

How do I protect it from being accessed across other websites and make it exclusive only through my domain?

Answer 1

Ensure the requestor has:

• HTTP_REFERER set to your site; and
• a valid cookie for your site.

This will prevent the behaviour that is most akin to hotlinking. However if a site uses an HTTP library to use your Web service and it's public there's not a lot you can do beyond IP throttling and similar techniques.