I'd like to only server requests that are made to a specific domain and just drop everything else or give it 404. Would prefer to see it done through nginx but would of course like the best solution.
When you setup Nginx, set your "server block" to be specific rather than general. This one would only pick up traffic going to www.domain1.com.
Where as this one would pick up all traffic to port 80.
More info: http://wiki.nginx.org/ServerBlockExample