Introduction to WebSphere Plug-in

-Plug-in is a glue between a Web Server and WebSphere
   Application Server
- Plug-in’s primary responsibility is to forward HTTP requests to
   the WebSphere Application Server
- The web server plug-in is developed native C language
- The plug-in code varies slightly depending on the operating
   system (OS) and the Web server being used although its
   operation and functionality remains the same.
- The plug-in code is in the form of a DLL library on Windows®,
    and SO library on Unix® (ie. AIX®, Solaris®, and so on).
- This library resides on the Web server machine and is loaded
    by the Web server startup process


Plug-in is an Agent:
You can think of the WebSphere plug-in as an “agent”
using the HTTP protocol.
redirecting HTTP requests from the WebServer to the application server
As seen in Figure 1, an HTTP request from a Web browser enters the Web server
and is then redirected to the application server.
This redirection is performed by the WebSphere plug-in.

 Plug-in Operation:
-The plug-in “sends” HTTP requests, and acts as an HTTP
  client.
-The application server receives those requests, and is
  therefore an HTTP Server.
- The component inside the application server which does the
  job of an HTTP Server is known as the HttpTransport.
-The HttpTransport of the appserver, listens on specific ports
  for HTTP (ie. 9080) and for HTTPS (ie. 9443).
-If there are multiple application server on the same node,
they must be configured to use unique port numbers.