nginx default page configuration

We have nginx setup which is used as a reverse proxy connecting to an apache backend. We are using varnish between them for caching. We need to set a default landing page if only domain name is given. we don't wish to set the index page on apache, we want to do it explicitly on nginx.

We know a method where the nginx can serve the default page from the local directory. What we want to achieve is to set the default page which is present on the apache server only.

Any ideas ?

Regards,

Viral