IIS/ DNS problem

I am trying to setup the DNS service on my IIS server. I added a host entry to the DNS manager for our domain name(host.domain.com) and I set it up in IIS as a new web site using ‘host’ as the header name (since the server only has one FQDN and one IP address available for all sites). When I connect to host.domain.com it goes to domain.com and not the host website. Is there some setting that I have entered wrong or is there something else I need to do to get it to connect to one of the other sites on the server?