Krdytkyu

I need to do a graphical map of all the layer-2 and layer-3 machines running in my LAN.

I don't want a graphical tool like Dia or similar, but a kind of "graphical Nmap" which shows the real cabling of the LAN (including switches, too!).

In fact, something like this: http://www.solarwinds.com/network-topology-mapper.aspx

To my knowledge, there are few comparable software packages available, free and out-of-the-box, for Ubuntu that don't require quite a bit of manual configuration.

OpenNMS might come close for your needs.

The Network Topology Mapper(and the SolarWinds Tool Suite, in general) is a very good, mid-level, network management tool. Unfortunately, it is Windows only and comes with a significant price tag. Without a great deal of customization, you will be hard-pressed to find a comparable solution. If you have the budget and run a heterogeneous shop, I can strongly recommend using this piece of software. Also, their IPAM and NetFlow tools are quite solid, as well.

That said, I know of three pieces of software that run on Linux and might give you a start dynamically mapping your network: Cheops, OPManager, and OpenNMS.

I would also recommend looking at the SLAC page to see if there are any more recent developments in the network management space.

The following applications are listed, in ascending order, in terms of cost, complexity, and feature-sets.

Cheops

Cheops is a free network mapping solution that will go out and discover and graphically display the servers and network nodes for you. It is old, and possibly no longer under development. But, it is a simple tool to use for network discovery.

You can download Cheops, here

OpenNMS

OpenNMS is able to do network discovery, event management, and performance management. It is available as a .deb package as well.

Core features:

• Automatic Layer-2 and Layer-3 link discovery


• Automatic Network / Node Discovery and Provisioning


• Automatic Service Discovery and Provisioning


• IPv6 support throughout (new)


• Manual Node and Service Provisioning Requisitions


• Path Outage support

Feature list

OpenNMS download

Installation instructions for deb/apt-get.

OPManager

OpManager, on the other hand, is a commercial tool. It has a similar feature-set of the SolarWinds solution. In my experience, it is very robust and customizable. That said, you will have to pay for it. It does run on Debian-based systems, though it is not custom-tailored for Ubuntu. YMMV.

In terms of network management functionality, it supports:

• Availability and Uptime Monitoring


• Traffic and Utilization Monitoring


• Cisco Monitoring


• Network Device Health Monitoring
  (Router, Switch, Firewall, wireless access points)


• Network Mapping


• Custom Network Maps / Network Traffic Maps


• WAN RTT Monitoring


• Network Traffic Analysis (NetFlow, sFlow)


• VoIP Monitoring


• Network Configuration Management


• IP Address Management


• Switch Port Mapper

For a full list of features, see:
here

You can download a free trial of OPManager here

I would be very interested in hearing from others in regards to using a free, unified network management solution in Ubuntu that does not require in-house development and a great deal of care and feeding.

In the mean time, when it's unreasonable to use OPManager, or OpenNMS, I will have to make due with my own custom Nagios/Cacti/SmokePing/Rancid/IPPlan solution for smaller networks.

A tool I've used and loved for ages is EtherApe, which may be another possibility you may want to check out. (In this case 10.0.0.2 is my adsl router)