$ ping -c1 -p 004f438e6380c869e76b7a9d86d12100 unhack.ca
 
$ curl http://unhack.ca/p/4f438e6380c869e76b7a9d86d121
 
$ dig 4f438e6380c869e76b7a9d86d121 @unhack.ca
 
$ dig 4f438e6380c869e76b7a9d86d121.ns.unhack.ca
 
C:\> nslookup 4f438e6380c869e76b7a9d86d121 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/4f438e6380c869e76b7a9d86d121">]>
    <foo>&xxe;</foo>
 
Waiting for ping...