Apache and nginx on same server with multiple IP addresses

In order to get this to work, you need to specify the IP and port each should listen in the domain configuration file (and NOT in the global web-server config).

nginx configuration for a domain (/etc/nginx/sites-enabled/www.mydomain.com) contains:

server_name http://www.mydomain.com mydomain.com;

Apache configuration for another domain contains:

In this case, this was at the top of /etc/apache2/sites-enabled/myotherdomain.com

WIth this setup, each web server has its own IP to listen to and they both serve on port 80.