Setting Up and Configuring a DHCP Server on OpenBSD

Last updated: Nov 1, 2023

In this guide, I will demonstrate how to use the robust and secure OpenBSD to set up a DHCP server.

Recently I had the need to configure a DHCP server for a Wi-Fi guest network, and OpenBSD is the ideal solution for this task. It's a lightweight, highly secure, and stable choice.

Property of the DHCP:
- Network: 192.168.1.0/24
- Gateway: 192.168.1.254
- DHCP range: 192.168.1.20 to 192.168.1.200
- DNS: 8.8.8.8 and 192.168.1.1
- domain: wifiguest.std.rocks

Configuration

Note: For reference, there is an example file, /etc/examples/dhcpd.conf, available on the system.

Create and edit a /etc/dhcpd.conf file:

#       $OpenBSD: dhcpd.conf,v 1.1 2014/07/11 21:20:10 deraadt Exp $
#
# DHCP server options.
# See dhcpd.conf(5) and dhcpd(8) for more information.
#

option  domain-name "wifiguest.std.rocks";
option  domain-name-servers 8.8.8.8, 192.168.1.1;

subnet 192.168.1.0 netmask 255.255.255.0 {
        option routers 192.168.1.254;

        range 192.168.1.20 192.168.1.200;

	#if needed to specify static address
	#host static-client {
	#	hardware ethernet 11:11:11:aa:aa:aa;
	#	fixed-address 192.168.1.30;
	#}

}

Enable and start the dhcpd service

Enable the dhcpd service to run automatically at boot:

OpenBSD# rcctl enable dhcpd

Start the dhcpd service:

OpenBSD# rcctl start dhcpd

Verify the status of the dhcpd service:

OpenBSD# rcctl check dhcpd

View DHCP Leases

Display DHCP leases:

OpenBSD# cat /var/db/dhcpd.leases
lease 192.168.1.20 {
        starts 3 2023/11/01 14:15:24 UTC;
        ends 4 2023/11/02 02:15:24 UTC;
        hardware ethernet 63:a0:03:59:23:b3;
        uid 01:63:a0:03:59:23:b3;
}

Computing

Music

Misc

Setting Up and Configuring a DHCP Server on OpenBSD

Configuration

Enable and start the dhcpd service

View DHCP Leases