Navigating Network Connections: How Windows 10 Handles Multiple Network Interfaces

When your Windows 10 machine is connected to two networks simultaneously, such as a Wi-Fi network from a public source and an Ethernet connection to your own router, the system determines which network to prioritize for internet traffic using a combination of the metric system, routing tables, and network profiles. This article explores in detail how this process works, the factors that influence the choice of network, and how you can adjust these settings to suit your needs.

The Metric System in Windows 10

The metric system is a critical component of how Windows 10 handles multiple network connections. Each network interface is assigned a metric value that determines its priority. Lower metric values indicate higher priority. By default, Ethernet connections have a lower metric value than Wi-Fi connections, ensuring that they are usually preferred for internet traffic.

Routing Tables in Windows 10

Windows 10 maintains a dynamic routing table that contains information about how to route network traffic. This table includes network interface information, destination IP addresses, and metric values. When you attempt to access a network resource, Windows checks the routing table to determine which interface to use. The route with the lowest metric that matches the destination IP address will be selected for internet traffic.

Network Profiles: Public, Private, and Domain

Each network connection can be configured with a specific profile: public, private, or domain. These profiles can influence certain settings like firewall rules and sharing options, but they do not significantly alter the routing priority. The system uses the metric system to determine which network to prioritize for internet traffic.

Internet Traffic Handling: Default Gateway and DNS Resolution

When connected to multiple networks, the handling of internet traffic is controlled by the default gateway. If both connections have a default gateway, the IP address used for internet access is determined by the metric value. The connection with the lower metric will be used for internet traffic. However, if the Wi-Fi connection has a higher metric, it may still be used for local traffic but not for internet-bound traffic.

Regarding DNS resolution, the DNS server used for resolving domain names is typically derived from the connection with the highest priority (and thus the lowest metric). If both connections provide DNS, the one with the lower metric will be used for DNS resolution.

Changing Priority: Manual Adjustments

If you need to change the priority of your network connections, you can do so manually with the steps outlined below:

Go to Control Panel Network and Internet Network Connections. Right-click on the connection you want to prioritize (Ethernet or Wi-Fi) and select Properties. Click on Internet Protocol Version 4 (TCP/IPv4) Properties Advanced. In the Advanced TCP/IP Settings, you can adjust the interface metric.

By adjusting the metric values, you can control which network is used for internet traffic, ensuring that your primary network has the highest priority.

Understanding and configuring your network connections can significantly impact your overall internet experience. Whether you are managing public and private networks, ensuring efficient internet traffic routing, or simply optimizing your network settings, these principles and methods are essential for effective network management in a dual-network scenario.