Support source IP interface for system DNS 7.6.1

Previously the local IP addresses could differ on each unit in a cluster, and the source-ip setting for DNS could not be synchronized across the cluster. This feature introduces a new source-ip-interface configuration option for DNS, ensuring consistent DNS configurations across the cluster and enhancing the overall network management experience.

config system vdom-dns
    set vdom-dns enable
    set source-ip-interface <string>
end

set source-ip-interface <string>

Specify an interface to use the IP address of the specified interface as the source IP address. Requires vdom-dns to be enabled.

config system dns
    set source-ip-interface <string>
end

set source-ip-interface <string>

Specify an interface to use the IP address of the specified interface as the source IP address.

Example

In this example, a private DNS is used. Port2 is configured with an IP address, and the private DNS is configured to use the IP address for port2 as its source IP address.

To set the source IP interface for a private DNS:

1. Configure port2 with an IP address. You can either specify an IP address or configure the interface tor receive an IP address from a DHCP server.

   Example fixed IP address configuration:

   config system interface
       edit "port2"
           set vdom "vdom1"
           set ip 10.1.100.1 255.255.255.0
           set allowaccess ping https ssh snmp http telnet
           set type physical
           set snmp-index 4
           set secondary-IP enable
       next
   end

   Example DHCP configuration:

   config system interface
        edit "port2"
            set mode dhcp
        next
   end

2. Configure port2 as the source IP interface for DNS:

   config system dns
       set primary 172.17.254.148
       set secondary 172.17.254.151
       set source-ip-interface "port2"
   end

3. Sniff port2:

   # diagnose sniffer packet port2 ""
   ....
   3.336987 10.1.100.1.2264 -> 172.17.254.148.53: udp 43