MacOS Split DNS not working with VPN profile

Introduction

This article explains how to configure Split DNS on a MacOS system when using a VPN profile. Split DNS allows you to use different DNS servers for different network interfaces. This can be useful when you want to access resources on both a local network and the internet simultaneously while connected to a VPN.

Prerequisites

Before you begin, make sure you have the following:

• A MacOS system with the latest updates installed
• A VPN client installed and configured

Split DNS configuration setup

To configure Split DNS on your MacOS system, follow these steps:

1. Open the Terminal application.
2. Run the following command to open the scutil configuration file:

sudo nano /etc/resolv.conf.d/scutil.conf

Replace "nano" with your preferred text editor if you don't have it installed.

3. Add the following lines to the file:

__:0:1:localhost
 __:0:2:fe80::1
 __:0:3:127.0.0.1
 __:0:4:192.168.11.41
 __:0:5:192.168.11.41

Replace "192.168.11.41" with the IP address of your local DNS server.

4. Save and close the file.
5. Run the following command to set up the VPN interface:

sudo scutil --dnsresolver State --set interface "en0" 1
 sudo scutil --dnsresolver searchdomain --set interface "en0" "my-domain.com"
 sudo scutil --dnsresolver nameserver --set interface "en0" 8.8.8.8
 sudo scutil --dnsresolver nameserver --set interface "en0" 8.8.4.4

Replace "en0" with the name of your VPN interface.

6. Run the following command to set up the Wi-Fi interface:

sudo scutil --dnsresolver State --set interface "en1" 0
 sudo scutil --dnsresolver searchdomain --set interface "en1" "my-domain.chn"
 sudo scutil --dnsresolver nameserver --set interface "en1" 192.168.11.41
 sudo scutil --dnsresolver nameserver --set interface "en1" 192.168.11.41

Replace "en1" with the name of your Wi-Fi interface and "my-domain.chn" with the name of your local network domain.

Troubleshooting

If you're experiencing issues with Split DNS, try the following:

• Check that your VPN client is connected and functioning properly.
• Check that your local DNS server is reachable.
• Check that your MacOS system is using the correct DNS servers for each interface. You can use the following command to check:

scutil --dnsresolver searchdomain --get interface "en0"
 scutil --dnsresolver searchdomain --get interface "en1"

References

For more information, check out the following resources:

• Apple Support: Configure DNS search domains
• Apple Support: Set up a VPN on Mac