LMS / CM / User Tracking subnet and group information

Unanswered Question
Jun 11th, 2009

Hello everybody,

I think I need someone to clarify subnet and groups usage in user tracking on LMS (3.0.1).

In the subnet acquisition window, I see only a part of our network subnets.

Is it possible to manually modify that list?


(someone else deployed LMS before I come, he's not there anymore)

I read that UT doesn't work with class A or B subnets; is that the cause (at least one of the subnets not shown is a private class B)?

Why am I able to see the missing subnets (class B included) under "Subnet Based Groups

",in the "Group Administration and Configuration" window?

What are those groups used for?

Thx in advance,


I have this problem too.
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Joe Clarke Thu, 06/11/2009 - 09:02

The subnets are picked up from what UT acquires from the network. If UT has not acquired any users in those subnets, then they will not show up. In order for UT to know a user is part of a certain subnet, a supported layer 3 device with ARP entries for the end hosts must be Data Collected by Campus Manager.

gpellizzari Fri, 06/12/2009 - 00:37

So, i can tell my boss that I am right.

You confirm that, if no Layer3 device on those subnet is data-collected by LMS, UT cannot link discovered MACs with IPs.

Therefore, UT won't know that that particular MAC belongs to a certain subnet, since IP data is missing.

So, the subnet isn't displayed 'cause it's simply unknown.

So, no ARP request is sent in such cases (and relaying ARP traffic is completely useless).

Thanks jclarke for your reply, you helped quite a lot.



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