There is a cool open source network related project called NeDi. This application is definitely one of the best discovery tools that I have ever used. NeDi unfolds its full potential with Cisco’s CDP (Cisco Discovery Protocol) in the core of your network.

Features include:

Automated Network Discovery

• Automatically discovers Cisco network devices and learns how they connect to each other (network topology)

Beautiful Web-Interface

• Simple to use

Device Management

• Quickly telnet to a device with just a few clicks
• Make bulk configuration changes to many devices at once
• Archive device configurations and report configuration changes

Reporting

• Location of users on the network (DNS–>IP–>MAC–>Switch–>Port)
• Show which IP addresses are being used, and which ones are available
• Report by device name, type, serial number, software version, vlans, and much more!

Monitor Performance

• Graph traffic statistics on every interface
• View the available memory and CPU utilization of network devices

Monitor Availability

• Poll network devices
• Send email or SMS alerts when a device goes down

Monitor Errors

• Receive and display SNMP Traps from devices
• Receive and display Syslog messages from devices
• Display error rates on interfaces

To make things very simple, you can download a Linux distribution (Ubuntu) that has NeDi already installed and ready to configure. The configuration process has been simplified with having the required configuration files on the desktop, ready to be edited with just a few simple parameters. The only drawback on this one particular image, is that it is an entire Ubuntu installation (GUI included). This makes it easier for the newcomer to Linux, however it will take a while to download(823 MB image).

If your needing a very robust tool that will quickly go in and identify a network - keep this image handy in your VMware images toolbox.

http://www.vmware.com/vmtn/appliances/directory/184