Topology of network

[netboy]

Has anybody ventured to figure out how to create an automated topology map of your home network? ARP table alone is not enough and a network can have dump switches, managed switches, wifiextenders and can have multiple vlans etc. These "physical" connections cannot be parsed from pfsense.

[johnpoz]

@netboy dumb switches would be very difficult to auto discover, since they lack anything that could be discovered - they run no link layer type protocols, cdp, lldp, isdp or even snmp where you could gleen info of what is connected to them, etc.

You can always go old school and just draw up your topology. But yeah dumb switches going to be a mystery to really anything that would attempt auto mapping of the topology.

While some software might be able to discern there is a switch, it wouldn't be able to get any info about the switch, number of ports, model, etc.. What is connected to what port on it.

There are the lldpd and ladvd package that could help in your quest of mapping out your topology.

edit: If your devices support snmp, here is a pretty easy to use free tool.. That can draw you up a map.

https://www.lantopolog.com/

Its not all that pretty.. But can get the job done..

Took me all of like 2 minutes to get this map. You see it even lists my unifi APs (hallway,kitchen,guestroom) and if you click into one them you can see what is connected to that specific AP

But again if your switches are dumb? Or do not support snmp such a tool will not help.. For example its missing my little unifi flex mini switch that hangs off the sg300-10. Between the 300 and the nvr where the cameras are connected.

So for example here - it shows a switch, but no info about the switch - but the switch is on that 192.168.2.6 IP, but it doesn't support snmp :( So it doesn't actually show true topology.

But can gleen what is connect to the mini from the unifi controller topology - to bad you can't have it add non unifi stuff to the map - or it would be pretty slick tool.

And that 10.1.1.1 is the nvr switch

So its like this

sg300-10 - flex mini - nvr switch - cameras

But via snmp everything is just hanging off port 4 on the 300-10

I will have to look if the nvr support snmp - but I find it highly unlikely.

[netboy]

@johnpoz I have setup parent child relationship in my database and figured out a way to get the topology - i have parent-child relationship established of my network (includes my skeletion relationship which ARP table does not know) using this relationship and i have ARP table for lookup and was able to create a dynamic tree

I can edit and "enrich" the ARP table with serial# etc

What do you guys think of the design?

[johnpoz]

@netboy said in Topology of network:

I have setup parent child relationship in my database

what did you set this up in?

[netboy]

@johnpoz This is in mariadb database

[johnpoz]

@netboy So you are wanting to create your own topology table - not really a "map" if you will since I don't see mappings to what port, etc.

[netboy]

@johnpoz ports are scanned using nmap

[johnpoz]

@netboy not network ports, physical port..

This is what makes it a map - tells you what is connected to what.. See port gi2 of my sg300-10 is connected to port gi8 of my sg250-08

edit: see on my unifi flex mini

It lists the devices it sees on its port 1, and also that my printer is connected to its port 4, it lists multiple devices on port 1, because that is its uplink to nvr switch, where those cameras are connected.