To configure a VPN network in which two MikroTik clients (VPN Client A and VPN Client B) can see each other, as well as communicate with the LAN of the main VPN server, you need to follow several steps to ensure that the routes and policies of firewall allow proper traffic.

We explain how you could configure it:

Step 1: Configure the VPN on the MikroTik Server

1. Configure the VPN server in the main MikroTik. You can use protocols such as OpenVPN, L2TP/IPsec, or SSTP, depending on your security and compatibility needs.
2. Set IP addresses for the VPN interface. Make sure the IP address range does not overlap with local LANs or VPN client addresses.
3. Configure routes so that any traffic destined for VPN client networks will be routed through the VPN interface.

Step 2: Configure VPN Clients (A and B)

1. Establish the VPN connection on each MikroTik client towards the VPN server. Each client should have configurations consistent with the server parameters.
2. Assign static or dynamic IP addresses to each client within the range defined on the VPN server.

Step 3: Route Configuration on the VPN Server and Clients

1. On the VPN server, configure static routes that direct traffic between VPN clients and to the server LANs. For example, if VPN Client A is at 10.0.0.2 and VPN Client B is at 10.0.0.3, and the server's LAN is at 192.168.1.0/24, you need routes that allow these devices to communicate.
2. On each VPN client, make sure there are routes that allow communication with the server's LAN and the other VPN client.

Step 4: Firewall Configuration

1. Review firewall policies on the server and clients to make sure they allow the necessary traffic. This includes allowing VPN traffic as well as inter-client traffic and traffic to and from the server's LAN.
2. Set up specific rules to allow traffic between the VPN clients' IP addresses and the server's LAN subnets.

Step 5: Test and Verification

1. Perform connectivity tests from each VPN client to the other client and to the server's LAN using tools like ping o traceroute.
2. Verify that traffic is flowing correctly through the VPN and that all routes and firewall rules are configured correctly.

Additional considerations

• Security: Make sure VPN connections are encrypted and firewall policies are restrictive enough to protect the networks involved.
• Maintenance: Keep your MikroTik software up-to-date and periodically review settings to adapt to any changes in network or security requirements.

By following these steps, you can configure a VPN network in which MikroTik clients communicate with each other and with the VPN server's LAN, ensuring connectivity and security throughout the network.