Use Linux as Network Switch

We can use Linux bridge utilities to create virtual bridges to connect networks. This allows the server to function similarly to switches:

sudo apt install bridge-utils

reate bridge interfaces (br0, br1, etc.) for each subnet:

sudo brctl addbr br0
sudo brctl addif br0 eth0
sudo brctl addif br0 eth1
# Repeat for other subnets and interfaces...

Assign DHCP to Bridge Interfaces:

Assign DHCP server to bridge interfaces to provide IP addresses to connected devices:

subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.10 192.168.1.100;
    # Other DHCP options for this subnet
    interface br0; # DHCP for this bridge
}
# Repeat for other subnets and bridges...

This configuration is complex and involves setting up bridges to function like switches, handling DHCP services for each bridge, and enabling IP routing between subnets. It’s recommended to test and validate each step carefully in a controlled environment before applying it to a production network.

Enable Forwarding on Bridges:

Enable packet forwarding on bridge interfaces for routing between subnets:

sudo sysctl -w net.bridge.bridge-nf-call-iptables=1
sudo sysctl -w net.bridge.bridge-nf-call-ip6tables=1