A DHCP Relay agent is a network device that forwards DHCP packets between clients and servers that are on different subnets. When a DHCP client sends a request for an IP address, the relay agent intercepts this request and forwards it to the DHCP server, which may be located on a different network segment. Once the DHCP server responds with an offer, the relay agent forwards this offer back to the client.
The primary objective of the DHCP Relay is to enable clients in different subnets to communicate with a centralized DHCP server. This is especially useful in larger networks where a single DHCP server may need to serve multiple subnets. By using a relay agent, network administrators can reduce the complexity of deploying multiple DHCP servers and ensure efficient IP address assignment across the entire network.
In summary, the DHCP Relay facilitates the smooth operation of DHCP services across different network segments, allowing for centralized management of IP address distribution.
First we do as always
apt update
apt upgrade
apt install isc-dhcp-relay
After installation, we will need to configure the local network and the configuration files once again.
Change the address and the netmask to match your local network. After that, we will configure the DHCP server files.
This is where we assign the interfaces that we will define, one for the server and one for the failover in case the server shuts down.
In the highlighted line, you can see the line that needs to be configured, and with this, we would have the file configured.
After configuring IPv4 forwarding, we restart the networking.service to apply the changes, and now we should proceed with the failover configuration.