A sort list prioritizes A and AAAA records on certain networks when those records are included in responses, sorting them to the beginning of the list in the response. For example, you can define a sort list when a server has two interfaces and you want the DNS clients to prefer one interface because it has a faster link.
When you define a sort list on the NIOS appliance, you specify the following:

• • The IP address or network of the source of the query
  • The IP addresses or networks that the appliance lists first in its response when it receives a query from the corresponding source address

NIOS 8.1NIOS Administrator Guide (Rev. A)825
Configuring DNS Services

When the NIOS appliance receives a query from the specified IP address or network and the DNS lookup produces a response with multiple addresses, the NIOS appliance sorts the addresses so that those in the sort list are at the beginning of its response. This feature is also supported for the Infoblox-4030 appliance. For more information, refer to the Infoblox DNS Cache Acceleration Application Guide.

Defining a Sort List

To define a sort list for a Grid, member, or DNS view:

1. Grid: From the Data Management tab, select the DNS tab, expand the Toolbar and click Grid DNS Properties. Member: From the Data Management tab, select the DNS tab > Members tab -> member check box -> Edit icon. DNS View: From the Data Management tab, click the DNS tab -> Zones tab> dns_view check box -> Edit icon.

To override an inherited property, click Override next to it and complete the appropriate fields.

1. In the editor, click Toggle Advanced Mode.
2. When the additional tabs appear, click Sort List.
3. Click the Add icon and select either Any to define a sort list for any address and network, or Address/Network to define a sort list for a particular source IP address or network.
4. Do the following in the new row:
   • If you selected Address/Network, enter the IP address or network of the source of the query. The feature supports IPv4 or IPv6 values.
   • Click the Add icon beside the source IP address to add the preferred IP addresses or networks for the source. You can add as many IP addresses as necessary. When you add multiple IP addresses, you can change the order of the IP addresses. Select an IP address and drag it to its new position, or click the up or down arrow, as show inFigure 17.2.

Figure 17.2 Sort List
Click this Add icon to enter a new source IP address.






Click to expand/hide the sort list of each source address.







Click + to enter the preferred IP address or network for the specified source address. Click

• • • to remove an address from the list.

Click the arrow to move an address up or down on the list.







826NIOS Administrator Guide (Rev. A)NIOS 8.1
Configuring a DNS Blackhole List

1. Enter the IP address or network in the Prioritized Networks field. You can add as many IP addresses as necessary. When you add multiple IP addresses, you can change the order of the IP addresses. Select an IP address and drag it to its new position, or click the up or down arrow.
2. You can add additional information about the source address or network in the Comment field.
3. To add another source IP address or network, click the Add icon again. You can create a separate sort list for each source IP address or network.
4. Save the configuration and click Restart if it appears at the top of the screen.