Remote Monitoring & Management Help

Known Issue - Load Balancing Gateway

Network Discovery uses the IP and MAC address of the default gateway for network identification and issues may be experienced where the network is served by a load balancing gateway (for example Cisco’s Gateway Load Balancing Protocol).

In this configuration, multiple routers (with different MAC addresses) can respond to the IP address of the virtual gateway used to balance the load across these routers and lead to the inconsistent reporting of the MAC address associated with the default gateway IP address.

When the load balancer changes to a new gateway MAC address, the network is reported as offline, regardless of its actual state. As the association between the network and the MAC address has changed, it is now identified in the system as a new network which will not yet have been managed. If this new network is then placed under management, it will also go offline the next time the load balancer changes to a new gateway MAC address, and once again will appear as yet another new network.

To avoid this issue and ensure the network can consistently be monitored, we would suggest changing the default gateway used on at least one high availability computer on the network to bypass the load balancer and instead go directly through a specific gateway device (so both the IP and MAC addresses are consistent).

For redundancy, we would suggest changing the default gateway on multiple computers to point to the same gateway device. This makes sure that if one is unavailable, communication of the consistent network details may be maintained with the Dashboard.

Once the gateway changes have been applied, Network Discovery should be enabled for these devices. Network Discovery should also be turned off on all other devices (those which are still using the load balanced gateway) to prevent any of those devices ever becoming the discoverer for your network.

For the successful implementation of this change, the network should be unmanaged and its current Network Discovery Agents disabled before placing the network under management again. Otherwise discovery could still be performed by an agent on a computer that uses a load balancing gateway, resulting in the network again reporting as offline when the gateway’s MAC address changes.

The steps for removing then re-adding Network Discovery are covered below:

Remove the network from Network Discovery management

  1. Go to the Networks tab
  2. Right-click on the target network in the north pane (or from the Networks drop-down)
  3. Unmanage selected network
  4. OK to confirm

Disable the Current Network Discovery Agents

When originally set at the Client or Site level

  1. Settings
  2. Network Discovery Settings
  3. Expand the target Client and Site
  4. Settings: Off
  5. OK to apply

When originally set at the Device Level

  1. Right-click on the device in the north pane (or from the Server or Workstation drop-down)
  2. Edit Server or Edit Workstation
  3. Network Discovery
  4. Settings: Off
  5. OK to apply

Once these changes have propagated to the device and they are no longer running the Network Discovery Agent:

Enable Network Discovery Agents on the specific devices where the gateway was changed

  1. Right-click on the device in the north pane (or from the Server or Workstation drop-down)
  2. Edit Server or Edit Workstation
  3. Network Discovery
  4. Settings: On
  5. OK to apply

Once this change has completed and Network Discovery agent is running on the device, the network will then be discovered (this will take a few minutes):

Place the network under Network Discovery Management

  1. Go to the Networks tab
  2. Right-click on the target network in the north pane (or from the Networks drop-down)
  3. Manage selected network
  4. OK to confirm