Specifying which DNS Servers are Used

Regardless of the IP version, you can specify how SonicOS/X selects the DNS servers. The method is the same for both IP versions.

To specify which DNS servers are used

1. Navigate to Network | DNS > Settings.
2. In the IPv4 DNS Settings or IPv6 DNS Settings section (depending on which version you chose), select one of the following:
   • To manually specify the DNS servers:
     1. Select Specify DNS Servers Manually.
     2. Enter up to three IP addresses into the DNS Server # fields.
   • To use the DNS Settings configured for the WAN zone, select Inherit IPv4/IPv6 DNS Settings Dynamically from WAN Zone. This is the default. The IP address(es) are populated into the DNS Server fields automatically.

3. If you selected IPv6, and want to use ONLY IPv6 servers, select Prefer IPv6 DNS Servers. This option is not selected by default.

   SonicOS/X DNS supports these server types:

   • DNS_SYSTEM_BEHAVIOR – the system default behavior, which depends on the setting of this option.
   • DNS_PREFER_V4_DNSSERVER – IPv4 DNS servers preferred unless there is a failure, then IPv6 DNS servers are requested.
   • DNS_PREFER_V6_DNSSERVER: – IPv6 DNS servers preferred unless there is a failure, then IPv4 DNS servers are requested.

   Select this option only if you have configured the IPv6 DNS server correctly.

4. Click Accept to save your changes.