Free Monitor ToolScreenshot
Free monitor tool is a branch version of AthTek NetWalk. It has almost all the features which AthTek NetWalk Enterprise Edition has, except for a few limitations. You can use this free monitor tool for your network management 4 hours each day, to capture less than 50MB packets. The advanced features maybe somehow overkill to novice users, but it could be a good network monitoring tool in learning how to capture and analyze packets.