Use multiple DNS based on request host/IP

Question

Is it possible to use different DNS servers based on the ip or the requested hostname?

For example:

• for www.example.com the 8.8.8.8 DNS server should be used
• for any other request the 192.168.1.1 DNS server

Thank you! :)

Answer 1

You could set up your Mac as local DNS forwarder. You have to install bind, configure as your local DNS and configure named.conf (/etc/named.conf).

forward only;
forwarders{
  192.168.1.1;
};
zone "example.com" IN {
type forward;
    forwarders {8.8.8.8;};
};

---

The other hacky way, which I haven't tested is:

When you having two DNS servers in you /etc/resolve.conf, Mac should decide which DNS is best for you to use based on the routing (I think).

You should assign your Mac into two different networks. The best is to have two connections (LAN+WiFi) or two LAN connections, or at least two gateways, but you could try with one (which will be more complex).

This example is based on one. Basically create two networks like:

sudo ifconfig eth0 host 192.168.1.2 netmask 255.255.255.0
sudo ifconfig eth0:0 alias host 192.168.2.2 netmask 255.255.255.0

and then try to re-route your DNS servers and domains to specified interfaces.

route add -host 192.168.1.1 dev eth0:0
route add -host www.example.com dev eth0:0
route add -host 8.8.8.8 dev eth0:0

I don't know if this hacky way will work on one interface, but should work on two.

If you have two gateways (even if it's the same device), more probability it'll work.

If this method doesn't work, sorry (let me know). It should be improved based on some practical go-through.