You can configure the DNS Traffic Control properties at the Grid or member level. The member DNS traffic control properties are inherited from the Grid DNS traffic control properties unless you override them.
The following sections explain how to configure DNS traffic control properties for the Grid or a Grid member.

Configuring Grid DNS Traffic Control Properties

To configure DNS Traffic Control properties for the Grid:

1. From the Data Management tab, select the DNS tab, expand the Toolbar and click Grid DNS Properties.
2. In the Traffic Control tab, complete the following:
   • Extensible Attributes Source Types for Topology Rules: Specify up to four extensible attributes to use as source types when defining DNS traffic control topology rules. For information about the extensible attribute topology rules, see Defining Topology Rulesets.
     You can use either predefined EAs or your own. For information about predefined extensible attributes, see Managing Extensible Attributes. For information about creating custom extensible attributes, see Adding Extensible Attributes.
   • When DNS Traffic Control is enabled, direct traffic according to EDNS0 Client Subnet when possible: Select this checkbox to direct traffic according to EDNS0 client subnet option when DNS Traffic Control is processing DNS queries.
     You can enable the appliance to redirect traffic according to EDNS0 client subnet option when DNS Traffic Control is processing DNS queries that contain the EDNS0 client subnet option. When you enable this feature, DNS Traffic Control querying process uses the client address specified in the EDNS0 client subnet option of the DNS query and the appliance includes the EDNS0 client subnet option in the response message. If there are multiple EDNS0 client subnet options in a query, the appliance considers only the first option and ignores the other options. When this feature is disabled, DNS Traffic Control querying process ignores the EDNS0 client subnet option. For more information about EDNS0, see Using Extension Mechanisms for DNS (EDNS0).
   • Return DNS responses if there are no DTC responses available: Select this if you want the appliance to return DNS responses if no DNS traffic control responses are available.
   • Return the following type of response from DNSSEC signed zones: Select one of the following response types for DNSSEC-signed zones:
     • Signed
     • Unsigned
       For more information on the Signed and Unsigned modes, see Managing LBDN Records.
3. Save the configuration and click Restart if it appears at the top of the screen.

Configuring Member DNS Traffic Control Properties

To configure DNS Traffic Control properties for a Grid member:

1. From the Data Management tab, select the DNS tab -> Members tab -> member checkbox -> Edit icon.
   Alternatively, you can select the DNS tab -> Traffic Control tab, click Member DNS Properties in the Toolbar, and then select the required member.
2. In the TrafficControl tab, complete the following:
   • DTC Health Check Source: Select which NIOS network interface to use for the DNS traffic control health check. Choose one of the following:
     • ANY
     • VIP
     • LAN2
     • MGMT
     • IP (This is displayed only when you have configured additional IP addresses in the network settings. Specify the IP address of the source.)
   • When DNS Traffic Control is enabled, direct traffic according to EDNS0 Client Subnet when possible: To retain the same setting as the Grid, keep the inherited value. To override the Grid setting, click Override. For information, see the Configuring Grid DNS Traffic Control Properties section.
3. Save the configuration and click Restart if it appears at the top of the screen.