Explain the difference between Server.Transfer and response.Redirect.

Redirect and Transfer both cause a new page to be processed. The difference lies in the way the interaction between the client and the server occurs.

Response.Redirect messages the client browser asking it to request for another page.
e.g. if a browser is on page A which has a Response.Redirect, then it asked to request for another page B by the server. When the client browser requests for it, then it is provided with the requested page B.

With Server.Transfer, the browser is not requested to ask for another page. Instead it is directly provided with the page B. In this scenario, the browser address bar continues to show the address of the previous URL.