Configure Linux DHCP Server for multipale Network range

Managing DHCP (Dynamic Host Configuration Protocol) for a network with huge range of clients and specific branches or section of a co or etc in Linux requires careful planning and configuration to ensure efficient IP address assignment and network management. Here’s a high-level overview of setting up DHCP in Linux for such a network:
To configure a Linux server as a DHCP server for five network IP ranges with specific Ethernet interfaces and enable routing between these networks, you’ll need to set up DHCP services and configure IP routing. Here’s a step-by-step guide:

1. Identify Network IP Ranges and Ethernet Interfaces:

Let’s assume:

• Network 1: 192.168.1.0/24 (eth0)
• Network 2: 192.168.2.0/24 (eth1)
• Network 3: 192.168.3.0/24 (eth2)
• Network 4: 192.168.4.0/24 (eth3)
• Network 5: 192.168.5.0/24 (eth4)

2. Install DHCP Server on Linux:

Install the DHCP server package, such as isc-dhcp-server.

3. Configure DHCP Server:

Edit the DHCP configuration file /etc/dhcp/dhcpd.conf to define DHCP pools for each network range and associate them with specific Ethernet interfaces:

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 eth0;
}

subnet 192.168.2.0 netmask 255.255.255.0 {
    range 192.168.2.10 192.168.2.100;
    # Other DHCP options for this subnet
    interface eth1;
}

# Repeat similar configurations for the other subnets and interfaces...

Also you can use this template:

subnet 192.168.1.0 netmask 255.255.255.0 {
    range 192.168.1.10 192.168.1.254;
    option subnet-mask 255.255.255.0;
    option routers Router_IP_Address;
    option domain-name-servers DNS_IP_Address1, DNS_IP_Adress2;
    default-lease-time 600;
    max-lease-time 7200;
}

Note that you have to configure additional options like default gateway, DNS servers, lease duration, etc., as per your network requirements.

4. IP Forwarding and Routing:

Enable IP forwarding to allow routing between the networks:

sudo sysctl -w net.ipv4.ip_forward=1

Assign IP addresses to the specified Ethernet interfaces for each subnet:

sudo ip addr add 192.168.1.1/24 dev eth0
sudo ip addr add 192.168.2.1/24 dev eth1
# Repeat for other subnets and interfaces...

Note that thease IP addressing is temporary and for configure ethernets IP addresses on Linux Server you can see here

5. Routing Configuration:

Set up routing rules to ensure traffic can flow between the subnets:

sudo ip route add 192.168.2.0/24 via 192.168.1.1 dev eth0
sudo ip route add 192.168.3.0/24 via 192.168.1.1 dev eth0
# Add routes for other subnets via the appropriate interfaces...

Note:

• Replace the example subnets (192.168.x.0/24) and interface names (eth0, eth1, etc.) with your actual network details.
• Ensure DHCP server configurations and subnet definitions match your network setup.
• Adjust routing rules based on the specific connectivity requirements between the subnets.
• Always validate and test configurations in a controlled environment before applying them to a production network.

Monitoring and Logging:

sudo systemctl status isc-dhcp-server
tail -f /var/log/syslog

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

Instead of Level 5 (Routing) We can use alternative methods for more you can take a look here