Finding Which Content Delivery server are you on in sitecore

Sometimes Testing Purpose we need to find which delivery server are we on.you should create a server.html file and put it under root folder of your website it should has the Text like CD1 for CD1 server,create another server.html file and add root folder of CD2 containg Text:CD2. so when you browse the below url,you will see the respective message based on the server you are on.

[You Domain]/server.html