perusio

server {
    listen 80; # IPv4	  	
    listen [::]:80 ipv6only=on; # IPv6
  
    server_name ~^(?<thishost>[^.]+\.)?subdomain\.example\.com$;
    access_log off;

    location / {
        ## Resolve the upstream address using this DNS server or any other.
        ## Choose the one that suits you.