steam.conf

server {
        listen 80;

        sendfile on;
        server_name  ~^(content[0-9]+)\.steampowered\.com$ ~^.*\.cs\.steampowered\.com$ client-download.steampowered.com *.hsar.steampowered.com.edgesuite.net *.akamai.steamstatic.com content-origin.steampowered.com *.steamcontent.com;
        resolver 8.8.8.8 8.8.4.4;

        access_log /var/log/nginx/steam-access.log;
        error_log /var/log/nginx/steam-error.log error;

        location ~ ^/(depot|client.+\.zip.*$) {
            proxy_cache       cache;
            proxy_cache_key   "steam $uri$slice_range"; # $is_args$args
            proxy_set_header  Range $slice_range;
            proxy_cache_valid 200 206 3000h;
            proxy_pass        http://$host;
	    proxy_cache_lock on;

   	    proxy_ignore_headers Expires Cache-Control;

        }
        location / {
            proxy_pass http://$host;
        }
}