$ ping -c1 -p 0056e502dcb35d93981577b34bdd0d00 pingb.in
 
$ curl pingb.in/p/56e502dcb35d93981577b34bdd0d
 
$ dig 56e502dcb35d93981577b34bdd0d @pingb.in
 
$ dig 56e502dcb35d93981577b34bdd0d.ns.pingb.in
 
C:\> nslookup 56e502dcb35d93981577b34bdd0d pingb.in
 
<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/56e502dcb35d93981577b34bdd0d">]>
    <foo>&xxe;</foo>
 
Waiting for ping...