Is it Ok not to have default virtual host in Apache or Nginx?

Question

The title pretty much sums it up. Do I need to have a default vhost in Apache or Nginx?

Answer 1

I typically set my default virtual host as a "go away" with a 403 forbidden response/message:

<VirtualHost *>
 ServerName nohost
 ErrorDocument 403 "The website you requested was not found on this server"
 RewriteEngine on
 RewriteRule . - [F]
</VirtualHost>

Answer 2

No, you don't both support single server installation. It's just helpful if you're running multiple sites from the same server.