The "slower" and "headers analyzer" features can work thanks to a simple proxy server that WebSlower runs internally.

You can setup this proxy server using the Connection Settings fields in the Settings sheet.

The Remote Host indicates the host you want to test, in the example google.com.
The Remote Port indicates the port you want WebSlower connects the proxy, n
normally it’s 80 (the default HTTP port) but you can change if needed.
The Local IP indicates the local IP address on which you want WebSlower to make the proxy listen on. The combo box shows the list of all available local IP addresses, 127.0.0.1 (localhost) is the default one.
The Local Port indicates the port you want WebSlower makes the proxy listen on.
The Speed specifies the maximum bit per second (bps) for the connection. The combo box on the right side includes some predefined speeds.

The connection flow is described below:

A. The user makes a request to the internal web browser proxy (i.e. http://127.0.0.1:8081/).
B. WebSlower throttles the HTTP request and slows down to the Speed value.
C. The request is forwarded to the destination web server (i.e. http://www.google.com:80/).
D. The web server executes the HTTP request and returns to WebSlower the response.
E. WebSlower throttles the HTTP response and slows down to the Speed value.
F. The response is returned to the user.

Both the request and response are throttled and slowed down to better simulate a slow connection.

The proxy saves internally the HTTP request and response headers that will be available in the Headers Logs sheet for further analysis. The user can also save the complete HTTP request and response headers in XML format.