Configuring Tanium Client subnets

Separated subnets and isolated subnets provide methods for modifying the default peering behavior of Tanium Clients. Default peering settings define the boundaries of client subnets in the Tanium™ linear chain architecture. Before configuring separated or isolated subnets, be sure that you understand the behavior that the default settings define and the impact of your changes: see Tanium Client Management User Guide: Configuring Tanium Client peering.

For the permissions to view and manage the Tanium Client subnet configurations, see Configure Tanium Client subnets .

In Tanium Core Platform 7.4.3 or later, Tanium Servers write subnet configurations to the Tanium database and automatically synchronize them in an active-active deployment. On Zone Servers, you must manually configure and maintain a SeparatedSubnets.txt file and IsolatedSubnets.txt file.

In most environments, the separated and isolated subnets configurations are the same for all Zone Servers and Tanium Servers. Keep the configurations synchronized across servers to avoid confusion. In complex environments with overlapping subnets, you might have to segregate subnets differently for Zone Servers. In such cases, modify the subnets configuration on each Zone Server that requires a unique configuration.

The following figure illustrates a deployment with where internal Tanium Clients connect with Tanium Servers in an active-active deployment and external clients connect with the Zone Server. This example shows separated subnets and isolated subnets within the linear chains that the default peering settings define.

The following figure shows the Tanium database on a dedicated host in a Windows deployment. However, in a Tanium Appliance deployment, the database is on the same host as the Tanium Servers.

Figure  1:  Tanium Client peering

Configure separated subnets

Tanium Clients in a separated subnet can peer only with other clients that are within that subnet. Configure separated subnets to specify more granular exceptions for Tanium Client peering than the default /24 subnet boundaries that the address mask or prefix settings define (see Tanium Client Management User Guide: Address mask and prefix settings). Clients use the separated subnets configuration for peering based on whether they connect to the Tanium Server or Zone Server. Each server uses the configuration to manage the peer lists for clients that register through it. After you configure separated subnets, you do not have to restart the servers.

After you configure separated subnets, Tanium Clients take two to six hours (the randomized client-reset interval) to finish applying all the changes associated with the new configuration. To verify that the separated subnets work as expected after the clients register, see Tanium Client Management User Guide: Verify Tanium Client peering and leader connections.

Configure separated subnets on the Tanium Server

  1. From the Main menu, go to Administration > Configuration > Subnets.
  2. In the Separated Subnets section, click New Subnets.
  3. Enter each separated subnet in CIDR format (such as: 192.168.2.0/26), with one line per entry. Use the ; or # character before any optional comments.

    Tanium Core Platform 7.3 or later supports IPv6 subnets (for details, contact Tanium Support at [email protected]). You must enter IPv6 subnets within square brackets followed by the prefix (such as: [2001:db8::]/32).

    See the following example:

    192.168.0.0/26 #This is a data center subnet.
    192.168.2.0/26 ;This is a branch office subnet.
    [2001:db8::]/32

    If a deployment includes Zone Servers, copy entries from the text field to the clipboard to use when you configure separated subnets on a Zone Server.

  4. Click Save.

Configure separated subnets on a Zone Server

If a deployment includes Zone Servers, perform the following steps based on your Tanium infrastructure to add a separated subnets configuration to each server.

Windows infrastructure

  1. Create a plain text file named SeparatedSubnets.txt.
  2. Copy and paste the separated subnets information that you entered for the Tanium Server into SeparatedSubnets.txt.

    If you did not already copy the information to the clipboard, go to Administration > Configuration > Subnets, select the separated subnets configuration, click Edit, and copy the entries from the text field.

  3. Move SeparatedSubnets.txt to the installation directory of each Zone Server (the default installation directory is \Program Files (x86)\Tanium\Tanium Zone Server). If necessary, you can modify the file contents for each Zone Server that requires a unique configuration.

Tanium Appliance infrastructure

  1. On the Zone Server appliance, sign in to the TanOS console as a user with the tanadmin role.
  2. From the tanadmin menu, enter 2 to go to the Tanium Operations menu. ClosedView screen
  3. Enter 2 to go to the Configuration Settings menu. ClosedView screen
  4. Enter 12 to edit the SeparatedSubnets.txt file. ClosedView screen
  5. Use the menu to specify subnets in CIDR format.

Configure isolated subnets

Configure isolated subnets to disable client peering for a specified list of subnet and endpoint IP addresses. If the IP address of a Tanium Client is in an isolated subnet, TaaS the Tanium Server or Zone Server sends that client an empty peer list to prevent the client from participating in peering.

After you configure isolated subnets, you do not have to restart the Tanium Servers or Zone Servers. Tanium Clients take two to six hours (the randomized client-reset interval) to finish applying all the changes associated with the new configuration. To verify that the isolated subnets work as expected after the clients register, see Tanium Client Management User Guide: Verify Tanium Client peering and leader connections.

Configure isolated subnets for Tanium Clients that are in VPNs. VPN clients have local IP addresses in a special VPN address block, but their host endpoints are actually not close to each other. VPN clients would use WAN links for peering and latency would be significantly greater than for client-to-server connections.

You might find it convenient to use isolated subnets to disable peering in other cases, such as for testing or debugging peering when you have to troubleshoot network issues. Note that disabling peering causes Tanium Clients to consume more network resources in terms of bandwidth and client-server connections over the WAN. For troubleshooting cases, after you resolve the network issues, the best practice is to remove the clients from the isolated subnets configuration so that they resume peering.

Configure isolated subnets on the Tanium Server

  1. From the Main menu, go to Administration > Configuration > Subnets.
  2. In the Isolated Subnets section, click New Subnets.
  3. Enter each isolated subnet in CIDR format (such as 192.168.2.0/26), with one line per entry. Use the ; or # character before any optional comments.

    Tanium Core Platform 7.3 or later supports IPv6 subnets (contact Tanium Support at [email protected]). You must enter IPv6 subnets within square brackets followed by the prefix (such as [2001:db8::]/32).

    See the following example:

    192.168.0.0/26 #This is a data center subnet.
    192.168.2.0/26 ;This is a branch office subnet.
    [2001:db8::]/32

    If the deployment includes Zone Servers, copy entries from the text field to the clipboard to use when you configure isolated subnets on a Zone Server.

  4. Click Save.

Configure isolated subnets on a Zone Server

If the deployment includes Zone Servers, perform one of the following procedures, depending on whether you want to isolate all clients or clients on specific subnets, and your Tanium infrastructure.

The Zone Server applies the most restrictive rule to determine the subnet for a client. If you configure the zs_address_mask or AddressMask setting to isolate clients, that setting overrides any subnet-based isolation that is configured in an IsolatedSubnets.txt file.

Isolate all clients connected to any Zone Server

Set the zs_address_mask global setting on the Tanium Server (Administration > Management > Global Settings) to 4294967295, which specifies /32 subnet boundaries (single hosts) for all Zone Servers.

For more information, see Tanium Client Management User Guide: Address mask and prefix settings.

Isolate all clients connected to a particular Zone Server

  1. Sign in to the Zone Server host as an administrator user.
  2. Access the CLI (see Tanium Core Platform Deployment Reference Guide: Command-line interface).
  3. Navigate to the Zone Server installation folder:

    > cd <Zone Server>

  4. Configure the AddressMask local setting to specify /32 subnet boundaries (single hosts):

    > TaniumZoneServer config set AddressMask 4294967295

For more information, see Tanium Client Management User Guide: Address mask and prefix settings.

Isolate clients on specific subnets with Windows infrastructure

  1. Create a plain text file named IsolatedSubnets.txt.
  2. Copy and paste the isolated subnets information that you entered for the Tanium Server into IsolatedSubnets.txt.

    If you did not already copy the information to the clipboard, go to Administration > Configuration > Subnets, select the isolated subnets configuration, click Edit, and copy the entries from the text field.

  3. Move IsolatedSubnets.txt to the installation directory of each Zone Server (the default installation directory is \Program Files (x86)\Tanium\Tanium Zone Server). If necessary, you can modify the file contents for each Zone Server that requires a unique configuration.

Isolate clients on specific subnets with Tanium Appliance infrastructure

  1. On the Zone Server appliance, sign in to the TanOS console as a user with the tanadmin role.
  2. From the tanadmin menu, enter 2 to go to the Tanium Operations menu. ClosedView screen
  3. Enter 2 to go to the Configuration Settings menu. ClosedView screen
  4. Enter 11 to edit the IsolatedSubnets.txt file. ClosedView screen
  5. Use the menu to specify subnets in CIDR format.