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New Member

LMS 4.1 Usertracking & VTP mode transparent

Hello community,

I am facing the following issue. In our environment we have a couple of WS-C2960S-24TS-L configured as stack. These switches are configured as VTP mode transparent.

We are running LMS 4.1 and although UserTracking Acquisition works fine for all other switches, it only runs on demand for the above. The user tracking report for these switches shows only the MAC of the connected end hosts, without the respective IP address. The vlan I am interested in is configured on both the gateway (cisco 6509) and the switches, and the subnet is routable.

Show arp on the gateway does show the "mac-ip address" binding, so I would have thought that usertracking would have been able to report both IP and MAC.

Summing up:

  1. Why does usertracking only run on demand for the above switches in vtp mode transparent?
  2. Why does the UserTracking report show only the MAC and not the IP?
  3. Are the above issues related to the vtp mode?

I have ruled out any connection to the switch-model, because we have recently installed the same switches in VTP mode client and UserTracking Acquisition works fine for them.

Any assistance will be highly appreciated.

Katerina

3 REPLIES
New Member

LMS 4.1 Usertracking & VTP mode transparent

As it turns out the above is the correct behaviour of LMS. Even if a switch is configured as VTP mode transparent, no matter in which VTP domain it exists, LMS will place it in VTP_domain_name_SwitchIP. It will never associate it with the gateway that has the IP-address of the Vlans, so there will never be a binding between mac - IP.

The only way to get the binding is to convert the switch to VTP mode client.

http://www.cisco.com/en/US/products/sw/cscowork/ps563/products_tech_note09186a0080094949.shtml#s2

Hope this helps someone facing a similar problem!

Regards,

Katerina

LMS 4.1 Usertracking & VTP mode transparent

It doesn't make sense to me.

If you see the endhost mac addresses in the switch reports for the various VLAN's then all you need to make sure is that the default gateway of the endhost is a managed router in LMS.

You say the VLAN goes to the 6509. So I guess there is a router blade in there?

Anyway, A VLAN does not have an IP address, It has a gateway. There is no binding with the VLAN, the switches running the VLAN are unaware of the gateway IP. Only the endhost should know, or hope it replies in proxy ARP.

This gateway is the only device that can make the link between the mac address and the IP address of the endhosts.

This has to be a cisco device, and it has to be a router or switch/router. Campus was and still is unable to load the ARP table from a PIX, ASA, etc.

Cheers,

Michel

New Member

LMS 4.1 Usertracking & VTP mode transparent

Michel,

I absolutaly agree with what you say, as a network engineer/administrator. But for LMS, a switch in transparent mode is a whole different thing. We opened a TAC for the above issue and that is the official reply.

As it turns out, something that I hadn't noticed in the user tracking reports, there are no associated routers (meaning any router or 3rd layer switch, which was our case), for transparent switches, so there can't be a L2 - L3 association in the reports.

Cheers,

Katerina

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