Updated on 14 Dec, 2023
The Split DNS functionality allows you to reach internal domain names while connected to the VPN, in the case when both External/Custom DNS and Split Routing features are activated on a UTunnel Access Gateway/VPN server.
By default, a DNS service is included on all UTunnel servers to avoid DNS leaks. When a VPN client device connects to the VPN, it will be using the UTunnel DNS server for name resolution. But, you may need to override this behavior if your organization is using an internal DNS server and if you want to resolve names on an internal/private domain. With the Custom DNS option, you can let VPN devices use your own DNS server for the name resolution.
When both split routing and external DNS are enabled, VPN client devices may use the DNS with the default route (LAN connection) instead of the DNS server offered by the VPN server. This will result in names on your internal/private domain not resolving when the VPN is connected. You can use the split DNS feature to override this scenario. Split DNS allows you to define your internal domain names for which the configured custom DNS server will be used.