$ ping -c1 -p 00cb4e7d2d1db9174eda3d5f3f100200 unhack.ca
 
$ curl http://unhack.ca/p/cb4e7d2d1db9174eda3d5f3f1002
 
$ dig cb4e7d2d1db9174eda3d5f3f1002 @unhack.ca
 
$ dig cb4e7d2d1db9174eda3d5f3f1002.ns.unhack.ca
 
C:\> nslookup cb4e7d2d1db9174eda3d5f3f1002 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/cb4e7d2d1db9174eda3d5f3f1002">]>
    <foo>&xxe;</foo>
Waiting for ping...