How to check if is anonymous user's first visit to site when using varnish If one has a Drupal 7 site which uses varnish for caching, is there some method which would enable one to serve a different version of front-page if it is first time the anonymous user has visited the site?

As I understand it, varnish caching will not work if a session variable is used. Is there some way of doing this using client side cookies?
The varnish caching will not work if you use cookies : http://systemsarchitect.net/2013/07/08/reading-php-session-from-varnish-cache/