wildcard virtual host allow you to host multiple web sites with one configuration file.
Here is what i use for bizhat.com free hosting sub domains.
server { listen 167.114.61.119:80; server_name *.bizhat.com; autoindex on; access_log /var/log/nginx/free_access.log; error_log /var/log/nginx/free_error.log; root /home/vhosts/$host; index index.html index.htm default.htm default.html; location ~* \.(jpg|jpeg|gif|css|png|js|ico|html)$ { access_log off; expires max; } location ~ /\.ht { deny all; } error_page 302 /302.html; location = /302.html { root /home/free.bizhat.com/error; } error_page 404 /404.html; location = /404.html { root /home/free.bizhat.com/error; } }