monline

"tcpmon is an open-source utility for monitoring the data flowing on a TCP connection. tcpmon is used by placing it in-between a client and a server. The client is made to connect to tcpmon, and tcpmon forwards the data to server along-with displaying it in its GUI."

Theoretically the above link takes you to the most recent version of tcpmon. However the project started as an Apache tool. At tcpmon.dev.java.net you can get v1.1 and at ws.apache.org v1.0. But the two are not identical featurewise! The new version lacks the ability to switch between horizontal and vertical layout and more importantly it lacks the XML rendering mode. The latter displays XML content structured, ie. the various nodes are indented based on their level in the XML tree. Unfortunately the old version uses some fixed size font which gets pretty much unreadable at higher resolutions.