split-horizon
also: split-view DNS, split DNS, view-based DNS
A DNS technique where a nameserver returns different IP addresses for the same domain depending on whether the query comes from inside or outside a network. This allows internal and external clients to resolve the same hostname to different destinations.
Split-horizon DNS (also called split-view DNS) serves different DNS responses based on the source of the query. Typically, internal network clients receive private IP addresses, while external internet clients receive public IP addresses for the same domain name.
For example, example.com might resolve to 10.0.0.5 (internal IP) when queried from inside your corporate network, but resolve to 203.0.113.42 (public IP) when queried from the internet. This is commonly implemented using separate DNS zones or conditional forwarding rules.
Split-horizon is useful for security (keeping internal infrastructure hidden from external view), simplifying access (internal users reach services via internal addresses), and disaster recovery scenarios where you want to redirect traffic based on network location.