Split DNS

Configuring Split DNS

In a split DNS infrastructure two DNS zones are created for the same domain, one to be used by Internal network and the other to be used by the external network. DNS on your internal network resolves to the  A split DNS routes the internal hosts to an internal domain name server for name resolution and external hosts are directed to an external domain name server for name resolution.

If you're using Mettle SE as the DNS server for internal hosts you can use DNS forwarder override to implement split DNS deployment. Adding an override to DNS forwarder, go to:
  1. LAN Services >> Basic LAN >> DNS
  2. Under Domain Over Rides click the 'Add New' button "You may enter records that override the results from the forwarders below"
  3. This brings up the DNS forwarder: Edit host screen You will need to add an override for each host name in use behind your firewall.

Example DNS overrides for mettle.in and www.mettle.in

Eg 1)
  1. Host:
  2. Domain: mettle.in
  3. IP Address:
  4. Description: Override for mettle.in web server
Eg 2)
  1. Host: www
  2. Domain: mettle.in
  3. IP Address:
  4. Description: Override for www.mettle.in
Internal DNS Servers

If using other DNS servers in your internal network like Microsoft Active Directory, you will need to create zones for all the domains hosted inside the network along with all other records for those domains.

In network scenarios with BIND DNS server where the public DNS is hosted on the same server as the private DNS, BIND's  views feature is used to resolve DNS differently for internal hosts and external ones.