When the win7 dual-nic is connected to the Intranet and Internet at the same time, two default gateways may conflict, resulting in the two networks being inaccessible.
Therefore, the solution is to configure only one gateway and use one static route for the other network.
Step 1: configure the Internet Nic as normal. Configure the Intranet Nic. Note that the default Intranet gateway is left empty.
Step 2: print the route and confirm that 0.0.0.0 is taken from the Internet gateway.
If the current default is not an Internet gateway, start cmd as an administrator, first route Delete 0.0.0.0,
Then add route 0.0.0.0 mask 0.0.0.0 zzz. Zzz. Zzz. ZZZ (external gateway ).
Step 3: Route add-P 192.168.100.0 mask 255.255.255.0 192.168.100.1 if 14
14 indicates the Intranet interface number, which can be seen in route print. -P indicates adding a static route, that is, it will not be lost after restart.