Domain Name Server Block. The UltraTools RBL Database Lookup checks to see if your domain is on a Real Time Spam Blacklist and whom you can contact to dispute the block. Maybe you were looking for one of these abbreviations.
NGINX does not have Virtual hosts it has Server Blocks that use the server_name and listen directives to bind to tcp sockets. - DOMA - DOMAI - DOMAIN - DOMAR - DOMASSGE - DOMATES - DOMCHA - DOMD. Server block files are what specify the configuration of our separate sites and dictate how the Nginx web server will respond to various domain requests.
DNS blocking can also be applied for outgoing requests as well.
When using the Nginx web server server blocks similar to the virtual hosts in Apache can be used to encapsulate configuration details and host more than one domain off of a single server. An easy way to test for a DNS server issue is by typing a websites IP address into the browser. Maybe you were looking for one of these abbreviations. Enter a domain name or an IP address.