View source for Debian 12: Installing and configuring a DHCP server

A DHCP server is required to allocate IP addresses to devices connected to the server directly or through a router. This service is usually used on local networks. In this guide, we will configure a DHCP server on which there are 2 external ports, 1 for connecting to the Internet and the other for the local network.

==1. Install packages==

 apt install isc-dhcp-server

===1.1 Pre-configuration===
In file:

 nano /etc/default/isc-dhcp-server

Let's uncomment the timing and bring the file to the form where in the INTERFACESv4 field we indicate the port for the local network, in our case enp1s0.

 DHCPDv4_CONF=/etc/dhcp/dhcpd.conf
 DHCPDv4_PID=/var/run/dhcpd.pid
 INTERFACESv4="enp1s0"

===1.2 Configuring the enp1s0 interface itself if it is not configured===

 /etc/network/interfaces

 auto enp1s0
      iface enp1s0 inet static
      address 100.100.100.1
      netmask 255.255.255.0

===1.2.1 Restart the service===

 service networking restart

===1.3 Basic settings for dhcp service===

 nano /etc/dhcp/dhcpd.conf

 option domain-name "localhost.localdomain";
 option domain-name-servers 100.100.100.1;
 default-lease-time 32400;
 max-lease-time 604800;
 log-facility local7;
 authoritative;
 
 subnet 100.100.100.0 netmask 255.255.255.0 {
    range 100.100.100.2 100.100.100.250;
    option broadcast-address 100.100.100.255;
    option routers 100.100.100.1;
 }

===1.3.1 Setting up a static IP by MAC address===

 nano /etc/dhcp/dhcpd.conf

 host mini-pc {
      hardware ethernet 06:e0:4c:6a:04:14;
      fixed-address 100.100.100.101;
 }

===1.4 Let's start the service and add it to startup===

 systemctl start isc-dhcp-server

 systemctl enable isc-dhcp-server

===1.5 Add rules to iptables===

 iptables -A INPUT -p tcp --dport 67 -j ACCEPT

 iptables-save > /etc/iptables/rules.v4

===1.6 Logging===

If it is necessary to include a log file, install the service:

 apt install rsyslog

Let's add the configuration:

 nano /etc/rsyslog.conf

 local7.* /var/log/dhcpd.log

Let's restart the service

 systemctl restart rsyslog

 systemctl restart isc-dhcp-server.service

A log file will be created and accessed at /var/log/dhcpd.log

The setup is complete, the server is configured and distributes IP addresses to devices connected via a port dedicated to the local network.

== Source ==

* [https://synay.net/en/support/kb/installing-and-configuring-dhcp-server-linux-debian-12 synay.net]
* [https://blog.programster.org/configure-dhcp-server-on-debian-12 programster.org]

[[Category:Linux]]
[[Category:Debian]]
[[Category:Router]]
[[Category:Tutorial]]