All IP-based networked devices, including computers, have routing tables. Routing tables describe the local network, remote networks, and gateways that you can use to forward traffic between networks. In networks with a single gateway, the routing table is very simple and indicates that local traffic should be sent directly to the local network, whereas traffic for any network other than the LAN should be sent through the gateway.
However, some networks have multiple gateways. For example, you might have two gateways on a LAN: one that leads to the Internet and another that leads to a private network. In that case, the local computer's routing table must describe that specific networks are available through the internal gateway and all other networks are available through the Internet gateway.
Note A client computer is most often configured with multiple routes in remote access scenarios. Specifically, if a client is using a virtual private network (VPN) connection, there might be separate routes for the networks accessible through the VPN connection, and all other traffic will be sent directly to the Internet.
Typically, computers running Windows will be automatically configured with the correct routing table. For example, network administrators will configure the DHCP server to assign a default gateway. When making a VPN connection, the VPN server will provide routing information that Windows will use to update the routing tables. Therefore, you rarely need to use the Route command to view or update the routing table.
However, if you are having connectivity problems and you are connected to a remote network or if your local network has multiple gateways, you can use Route to diagnose routing problems and even test different routing configurations. To view the local computer's IPv4 and IPv6 routing tables, open a command prompt and run the following command.
Fully interpreting the routing configuration requires a detailed understanding of IP networking; however, you can quickly identify default routes for traffic being sent to your default gateway by locating the Active Route with a Network Destination and Network Mask of 0.0.0.0 for IPv4 routes and an Active Route with the prefix ::/0 for IPv6 routes. Other Active Routes with a Gateway assigned cause traffic for the specific Network Destination and Network Mask to be sent through that gateway, with a preference for the route with the lowest metric.
If you must manually update the IPv4 routing table (you should typically make changes to the network infrastructure that assigned the routes to the client), you can use the route add, route change, and route delete commands. For more information, type route -? at a command prompt.
To update the IPv6 routing table, you must use the netsh interface ipv6 add|set|delete route commands.
In this tutorial:
- Troubleshooting Network Issues
- Tools for Troubleshooting
- Table-1 Network Troubleshooting Tools
- How to Identify a Problem with the ARP Cacher
- How to Clear the ARP Cache
- Event Viewer
- How to View Shared Folders on the Local Computer
- How to View Shared Folders on Another Computer
- Network Monitor
- Verifying that the Default DNS Server Resolves Correctly
- Verifying that a Specific DNS Server Resolves Correctly
- Verifying Specific Types of Addresses
- Using TCP for DNS Lookups
- PathPing Output
- Routing Loops
- Performance Problems
- Possible Connectivity Issues
- No Connectivity Issues
- Performance Monitor
- Data Collector Sets
- Windows Resource Monitor
- Identifying the TCP Port for a Service
- Windows 7 Testing Service Connectivity
- Determining Available Remote Management Protocols
- Why PortQry Is Great
- Task Manager
- Telnet Client
- Testing Service Connectivity
- Test TCP
- Windows Network Diagnostics
- The Process of Troubleshooting Network Problems
- How to Troubleshoot Network Connectivity Problems
- How to Troubleshoot Application Connectivity Problems
- Default Port Assignments for Common Services and Tasks
- How to Troubleshoot Name Resolution Problems
- How to Verify Connectivity to a DNS Server
- How to Use the Hosts File
- How to Troubleshoot Performance Problems and Intermittent Connectivity Issues
- How to Troubleshoot Joining or Logging on to a Domain
- How to Verify Requirements for Joining a Domain
- How to Troubleshoot Network Discovery
- How to Troubleshoot File and Printer Sharing
- How to Troubleshoot File and Printer Sharing from the Client
- How to Troubleshoot File and Printer Sharing from the Server
- How to Troubleshoot Wireless Networks
- Network Diagnostics
- How to Troubleshoot Firewall Problems