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Use the DNS Group - Server window to configure DNS servers for a DNS group within a specific address context. 

Note

The SBC Core supports up to eight DNS servers per DNS group. The SBC 5xx0/5400/7000 platforms support up to 2,048 DNS Groups system-wide. The SBC SWe supports up to 128 DNS Groups. Refer to SBC Provisioning Limits for additional provisioning limitations. 

To View DNS Group Servers

On the SBC main screen, go to Configuration > System Provisioning > Category: Base Provisioning > DNS > DNS Group > Server or
All > Address Context > DNS Group > Server

The Server window opens showing all configured DNS servers. Use the Address Context and DNS Group drop-down lists to filter the list.

DNS Group - Server

To Create a DNS Group Server

A DNS server must be associated with a specific address context and DNS group. To create a DNS server:

  1. Select the Address Context and DNS Group with which you want to associate the DNS server. The New Server option becomes available. 

  2. Click New Server. The Create New Server window is displayed.

    Create New Server Window

     
  3. Use the following table to configure the options and then click Save.


DNS Group - Server Parameters

Parameter

Description

Name 

The name for the DNS server.

State

The administrative state of the DNS server.

  • Disabled (default)

  • Enabled

Recursion Desired

Specifies whether to use recursion for the DNS server:

  • True (default)

  • False

IP Address V4 or V6 

Specifies the IP v4 or IPv6 IP address of the DNS server.

 

Transport Protocol

Specifies the transport protocol to use for DNS queries to the DNS server. Options are:

  • TCP

  • UDP (default)

TCP Fallback

Enable this option to support TCP fallback for queries to this server when the transport protocol is configured as UDP.

  • Disabled (default)

  • Enabled

Priority

Specifies the DNS server priority. Must be 0-100; default is 0.

Weight

Specifies the load-sharing weight for this DNS server. Must be 0-100,default is 0.

Record Order

Specifies the record lookup order for the DNS server. The options are:

  • Priority (default)—Specifies the lookup order is according to priority assignment.

  • Roundrobin—Specifies to share and distribute local records among internal SBC processes in a round-robin fashion. Over a large number of calls, a fair amount of distribution occur across all DNS records.

  • Centralized-roundrobin—Specifies that the calls will access DNS record entries in a round-robin fashion with respect to the whole system.

DSCP ValueSpecifies the Differentiated Services Code Point (DSCP) value the SBC sends in the IP header of DNS queries to the specified DNS server. The range allowed is 0 to 63. The default is 0

To Edit a DNS Group Server

To edit the configuration of a DNS group server:

  1. Click the radio button next to the server configuration you want to edit. The Edit Selected Server window opens.
  2. Modify the options as needed and click Save.

To Copy a DNS Group Server

To copy the configuration of a DNS group server and make changes to the copy:

  1. Click the radio button next to the server configuration you want to copy. The Copy Selected Server window opens.
  2. Modify the options as needed and click Save.

To Delete a DNS Group Server 

To delete the configuration of a DNS group server:

  1. Click the radio button next to the server configuration that you want to delete.
  2. Click the Delete (X) icon at the end of the row. 
  3. Confirm the deletion when prompted.


Note

Before deleting a DNS group, first delete the DNS local records and DNS servers in that group.