NetXMS Support Forum

It seems I can't get NetXMS to build a topology map with nodes unless I enable LLDP on them

Is there a way to show a layer 2 map based off just the MAC table instead? I would ideally like to be able to select a bunch of nodes, right click them and choose 'Show L2 Topology', place those nodes, have it scan the MAC table finding where each interface those nodes are on then draw links automatically and show me the port numbers as labels
I do this manually when I need to discover a new network and find where a specific device is, or create a basic network map. It would help a lot if I could have NetXMS do this work for me (without having to enable LLDP because some switches/routers don't support it, but they do support SNMP)

If NetXMS can't do this, is there a good simple program for automatically building network maps like this?

Hi,

actually NetXMS will use MAC address tables on switches to build network topology. There is also function "Find MAC address" where you can check if location of specific MAC is known. But connection between switch object and node object will only appear on layer 2 map if node's MAC address is the only MAC on switch port - otherwise server will assume that there are some unknown device in between. Also, if you are building automatic L2 maps, make sure that you have checked "include end nodes" option in map properties if you want to see node objects on the map.

Best regards,
Victor

Quote from: Victor Kirhenshtein on June 18, 2018, 09:58:10 PM
But connection between switch object and node object will only appear on layer 2 map if node's MAC address is the only MAC on switch port - otherwise server will assume that there are some unknown device in between

Is it possible for you to add an option to override this? I need a way to draw L2 maps between switches and they are always going to have multiple MAC's on the ports between them, even if directly connected with a cable. And even if it was an empty switch a lot of them are connected with point-to-point wireless so will show at least 3 MAC addresses.

I can think of 2 ways to do this
A)
An extra 2 options in map
- 'Draw every MAC address on port'
- 'Hide unknown/unmanaged nodes' so then I will only see the switches I have added to NetXMS, and it won't show computers
It would still have to do some filtering because if you have switches
A->B->C
Then it would look like A and B are connected to C. But if it goes through the MAC table on B it would see that A and C are on different ports. So A must be connected to B instead

B)
A new topology option:
Select multiple nodes in NetXMS, right click and choose Topology->Build links by MAC
And it would simply do Tool->Find MAC address for each of those nodes, take the result i.e. "SwitchA is connected to SwitchB on port 47", "Switch B is connected to Switch C on port 15" and show a map with nodes and links drawn based on the result