LAN has 2 networks: 192.168.15.0/24 and 192.168.2.0/24. NetXMS is 5.1.0/Windows.
When I run a discovery (active & passive), NetXMS finds over 400 additional subnets. None of the subnets have devices found in them; netxms only finds the subnets. See attached image for what I mean.
I have my 'Active Discovery Targets' set to 192.168.15.1 to 192.168.15.254. I understand why it is finding the 192.168.2.0/24 subnet, and the devices, and that's great.
But the other subnets are noise or a ghost or something. How can I hide them? I tried creating a new zone and was just going to dump them all there, but NetXMS doesn't allow me to move the subnets to the new zone.
Things I tried
1. A filter. Not possible, there are just too many. If NetXMS had the option to ! (negate) a filter, I could just put !(192.168.15.0/24,192.168.2.0/24) and that could work I guess. But it doesn't have a negation option.
2. I could use only active scan. I'm trying that now, after having just deleted all the other subnets. But I do arp monitoring, and I never see addresses for those other subnets, so I don't know why they're appearing in the first place. And honestly I'd rather just leave active + passive on.
3. Move the unwanted ones into a 'Junk' zone. But NetXMS doesn't let me move them.
So what can be done? Are all these subnets a symptom of some other issue, unrelated to NetXMS? How can I prevent them from appearing, or hide them?
TIA!
Update: Even though I switched to active only discovery, and deleted all the unwanted subnets, more are coming back.
Subnets are created on node configuration poll. Possible reason could be some node(s), which have interfaces with periodically changing IP address.
Filtering can be done in Hook::CreateSubnet script in script library, but first of all you can add some debug there (before "return true;" line):
trace(0, "In Hook::CreateSubnet | Conf poll on " .. $node.name .. " want to create subnet " .. $1.ipAddress);
This will add messages to server's log. If you NetXMS version is older then 5.x, line should be a bit different:
trace(0, "In Hook::CreateSubnet | Conf poll on " . $node.name . " wants to create subnet " . $1.ipAddr);