$ ping -c1 -p 00a340c170d2b7fbc6c0af7a6c283300 unhack.ca
 

$ curl http://unhack.ca/p/a340c170d2b7fbc6c0af7a6c2833
 

$ dig a340c170d2b7fbc6c0af7a6c2833 @unhack.ca
 

$ dig a340c170d2b7fbc6c0af7a6c2833.ns.unhack.ca
 

C:\> nslookup a340c170d2b7fbc6c0af7a6c2833 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a340c170d2b7fbc6c0af7a6c2833">]>
    <foo>&xxe;</foo>