Two NICs work together

Question

I got two NICs in my windows, one is Ethernet and the other one is wireless.

Now I want the Two NICs to work together

1. Use wireless to access the Internet. -> (192.168.1.0/24)

2. Use Ethernet to access local network.-> (172.16.1.1/24)

so I added something to the route table like this

Ipv4 Route Table
================================================================================
Active Routes:
Network Destination     Netmask          Gateway        Interface      Metric
      0.0.0.0           0.0.0.0          192.168.1.1    192.168.1.101  2
      127.0.0.0         255.0.0.0         On-link       127.0.0.1      306
      127.0.0.1         255.255.255.255   On-link       127.0.0.1      306
   127.255.255.255      255.255.255.255   On-link       127.0.0.1      306
===========================================================================
Persistent Routes:
Network Address         Netmask    Gateway Address  Metric
      0.0.0.0          0.0.0.0        192.168.1.1     1
     172.16.1.0      255.255.255.0    172.16.1.1      10
===========================================================================

the result is that I can access to the Internet, but it's VERY VERY slow.

any ideas?

Answer 1

If you only need to access computes in the 172.16.1.1/24 subnet on the ethernet network card just don't set any gateway on the NIC for that interface, windows does not support multiple gateways on disjointed networks.

The reason you are seeing slowness is Windows Dead Gateway Detection Algorithm is trying to get to the internet on your eithernet card without trying the wireless card. By only having one gateway it will immediately try the wireless card.

Here is a similar question to what you are asking where I go in to a little more depth and show how do do the setup via command line commands.

Answer 2

The pc will automatically forward any traffic going to 172.16.1.x to the ethernet interface (assuming it's correctly configured with an ip from this subnet, e.g. 172.16.1.10), there's no need for the route you are trying to add.

The pc will use the default route 0.0.0.0/0 only for traffic that is not going to 172.16.1.x.

Can you try to run the pc with the default routing tables without any changes, and see if this works ? Can you also provide the routing table with the default behaviour ?

Answer 3

Well, actually what I should do is very easy.
After connecting to the wired and wireless network, windows will setup route table automatically like the following.

Ipv4 Route Table
================================================================================
Active Routes:
Network Destination     Netmask          Gateway        Interface      Metric
  0.0.0.0               0.0.0.0          192.168.1.1    192.168.1.101  2
  0.0.0.0               0.0.0.0          172.16.1.1     172.16.1.1     2
  127.0.0.0             255.0.0.0         On-link       127.0.0.1      306
  127.0.0.1             255.255.255.255   On-link       127.0.0.1      306
127.255.255.255         255.255.255.255   On-link       127.0.0.1      306
===========================================================================
Persistent Routes:
Network Address         Netmask    Gateway Address  Metric
===========================================================================

there are two 0.0.0.0 in the Network Destination table. what I need to do is to delete the 0.0.0.0 with Interface 172.16.1.1, Use command route delete 0.0.0.0, but this will delete both of the Interface 192.168.1.1 and 172.16.1.1, so I need to add the interface 192.168.1.1 back, Use command route -p add 0.0.0.0 mask 0.0.0.0 192.168.1.1 if 13 metric 1(My wireless NIC id is 13) . Then this solved my problem. Thanks to @aseaudi and @Scott Chamberlain.