TCPMon

TCPMon Tutorial

• Introduction
• Structure and Dependencies
• Usage Patterns
• As an Explicit Intermediate
• As a Request Sender for Web Services
• As an HTTP Proxy
• Advanced Settings
• Slow Connection Simulation
• HTTP Proxy support

Introduction

TCPMon is a utility that allows the user to monitor the messages passed along in TCP based conversation. It is based on a swing UI and works on almost all platforms that Java supports. The aim of this simple tutorial is to explain how TCPMon works and also to explain some of its features.

Dependencies

TCPMon needs a JRE version 1.4 or higher.

Usage Patterns

As an Explicit Intermediate

The most common usage pattern for the TCPMon is as an intermediary. It is called explicit since the client has to point to the intermediary rather than the original endpoint in order to monitor the messages. The following figure explains this concept:

In order to start the TCPMon in this configuration one has to provide the host name and the port for the listener in the admin screen. See image below:

Pressing the "Add" button opens up a new tab that allows the messages to be seen as in the following screen:

At this point the requester should point to the listener port of the TCPMon instead of the original endpoint. Let us understand this with an example:

Say all messages passed between www.apache.org needs to be monitored.

Step 1 - Add a listener with host as www.apache.org and port as 80. Set the listener to port 8080 which may be any unused port in the local machine:

Step 2 - Send a request to localhost:8080:
$ curl http://localhost:8080/

Once the messages start flowing they can be seen in the relevant tab as seen below:

The bottom controls allow the messages to be XML formatted (useful in debugging Web services), save and resend the messages, and also to switch the layout of the message windows.

As a Request Sender for Web Services

TCPMon can also be used as a request sender for Web services. The request SOAP message can be pasted on the send screen and then sent directly to the server.

As an HTTP proxy

TCPMon can act as an HTTP proxy. To start the TCPMon at proxy mode, just select the "HTTP proxy" option from the radio buttons. When acting as a proxy, TCPMon only needs the listener port to be configured.

Advanced Settings

Slow Connection Simulation

TCPMon can simulate a slow connection, in which case the delay and the bytes to be dropped can be configured. This is specially useful in testing Web services.

HTTP Proxy support

If HTTP proxy support is required then that can also be set on the admin screen.