How to create 2 networks on one PC. the first with Internet access 2 local without Internet access?

Question

Computer networks

Good day to all!
How to create 2 networks on one PC. The first with access to the Internet at a speed of 100 megabits, 2 local without access to the Internet gigabit. On the local server, only servers (3 servers with two network cards) should communicate, when pumping everything goes through a 100 megabit grid. How to route traffic over a gigabit mesh?

Answer 1

Judging by the description, the computer has 2 network cards. And most likely each has a default gateway in the settings. So - a network card that works on a local network (gigabit) should not have a default gateway, in general, and it needs to be removed in the settings.
For a more accurate answer, you need a network diagram and settings for the network interfaces of all nodes of interest (computer, servers, ...).

Maybe the diagram will make it clearer.

Your scheme is such that there is a problem of recognizing the correct address. Servers advertise themselves on both the 192.168.29 network and the 192.168.30 network.
The simplest possible solution to the problem is to allocate one more name to each server, under this name register the servers in the HOSTS file (each server has only the other two, it is not necessary), specifying only the address from the 29th subnet. Communication between servers should be performed only by these names. at the same time - increase the metric of the network card from the 30th subnet.