How to configure dual network cards to connect to both internal and external networks at the same time

How to set up dual network cards to connect to both internal and external networks at the same time

For some companies that require high network security, the best solution is to use dual network cards to connect to the internal and external networks at the same time. So how to set up dual network cards to connect to the internal and external networks at the same time? One of the dual network cards can be used to access the internal network and the other to the external network. This can ensure the security of the internal network and solve the problem of the computer accessing the external network. Of course, the premise is that two network cards need to be installed on the computer and connected to the two network cards respectively. on a route. Since ordinary users basically do not need dual network cards, here is a brief explanation of the implementation method for professional technology:

How to set up dual network cards? Dual network cards can connect to both internal and external networks at the same time. Tutorial on how to set up dual network cards

First is the network IP address configuration example of dual network cards:

External network address setting Local IP address: 192.168.1.1

Subnet mask: 255.255.255.0,

Gateway: 192.168.1.1

Intranet address setting: local IP address: 192.168.42.129

Subnet mask: 255.255.255.0

After setting the IP of each network card normally (or automatically obtaining it through DHCP), we can use the route print command under cmd to view the routing table. If it is discovered that there are two gateways pointing to 0.0.0.0, this may cause a routing conflict, causing access problems to both networks. To solve this problem, we need to configure routing manually. Please note that when running the cmd command, if it is on a Windows 7/8 system, it needs to be run with administrator privileges.

The first step: route delete 0.0.0.0:: Delete all 0.0.0.0 routes

Step 2: route -p add 0.0.0.0 mask 0.0.0.0 mask 192.168.1.1:: Add 0.0.0.0 network route. This is the default route using 192.168.1.1. The purpose of adding -p is to set It is a static (permanent) route to prevent the configuration from disappearing the next time it is restarted.

The third step: route -p add 192.168.42.0 mask 255.255.255.0 192.168.42.132:: Add the 192.168.42.0 network segment route as the 192.168.42.132 intranet route. You can adjust the ip segment and subnet mask as needed. The effect of multi-segment intranet routing.

After execution, there will be two more permanent routes, as shown in the figure below:

Dual network cards are connected to both internal and external networks at the same time. Because what we added above is a static route, after restarting, the default network in the tcp/ip settings will become the active gateway, which will also cause routing conflicts. Therefore, we need to Remove the gateway in the tcp/ip settings of the intranet.

How can a computer with dual network cards connect to the internal network and the external network at the same time

There is no perfect solution for using dual network cards to access the internal and external networks at the same time, because there are routing conflicts. After all, there are two gateway addresses

Let’s first solve the problem of dual network card conflict. This can be done by changing the routing address table. Take your machine as an example. The machine has two network cards and is connected to two routers:

The intranet address is set to 192.168.1.110, subnet mask: 255.255.255.0, gateway: 192.168.1.1

External network address: 10.94.12.123 Subnet mask: 255.255.255.0, gateway: 10.94.12.254

If you set the IP address and gateway of each network card according to the normal setting method, you will see two things starting with 0.0.0.0 0.0.0.0 when you use route print under cmd, that is, pointing to 0.0.0.0 With two gateways, routing conflicts will occur and access to the two networks will be difficult. To access two networks at the same time, you need to use the route command

If not, enter path

Step one: route delete 0.0.0.0 (delete all routes of 0.0.0.0)

Step 2: route add 0.0.0.0 mask 0.0.0.0 192.168.1.1 (add 0.0.0.0 network route)

Step 3: route add 10.0.0.0 mask 255.0.0.0 10.94.12.254 (add 10.0.0.0 network route)

At this time, you can access two networks at the same time, but you encounter a problem. The routes added using the above commands will be automatically lost after the system restarts. How to save the existing routing table?

Make a BAT file, add all the contents of the above three steps, and set the system to run it in the startup menu. In this way, as soon as the computer is turned on, the routing table will be changed according to our needs, and there will no longer be problems with dual network access.

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