This guide will go over installing ISC dhcpd and using a custom systemd service for both v4 and v6 services (instead of the included one).
Install with APT
apt install isc-dhcp-serverDisable and Mask the included systemd service file
systemctl stop isc-dhcp-server.service && \
systemctl disable isc-dhcp-server.service && \
systemctl mask isc-dhcp-server.serviceCreate a new systemd service for dhcpd v4
bash -c "cat > /etc/systemd/system/dhcpd-v4.service"<<'EOF'
[Unit]
Description=ISC DHCPv4 Server Daemon
Documentation=man:dhcpd(8) man:dhcpd.conf(5)
Wants=network-online.target
After=network-online.target
After=time-sync.target
[Service]
Type=exec
Restart=on-failure
RestartSec=60
User=root
Group=root
ExecStart=/usr/sbin/dhcpd -4 -f -cf /etc/dhcp/dhcpd.conf --no-pid $DHCPARGS
StandardError=null
[Install]
WantedBy=multi-user.target
EOFReload and start the v4 dhcpd service
systemctl daemon-reload && \
systemctl enable --now dhcpd-v4.serviceCreate a new systemd service for dhcpd v4
bash -c "cat > /etc/systemd/system/dhcpd-v6.service"<<'EOF'
[Unit]
Description=ISC DHCPv6 Server Daemon
Documentation=man:dhcpd(8) man:dhcpd.conf(5)
Wants=network-online.target
After=network-online.target
After=time-sync.target
[Service]
Type=exec
Restart=on-failure
RestartSec=60
User=root
Group=root
ExecStart=/usr/sbin/dhcpd -6 -f -cf /etc/dhcp/dhcpd6.conf --no-pid $DHCPARGS
StandardError=null
[Install]
WantedBy=multi-user.target
EOFReload and start the v6 dhcpd service
systemctl daemon-reload && \
systemctl enable --now dhcpd-v6.serviceTo use two dhcpd servers in an Active-Active configuration.
Configuration
Add firewall rules to allow the two hosts to talk to one another. Don't forget to do the same on the other server, with the opposite IP source address.
firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=172.16.5.10/32 port port=7911 protocol=tcp accept' --zone=public
firewall-cmd --permanent --add-rich-rule='rule family=ipv4 source address=172.16.5.10/32 port port=520 protocol=tcp accept' --zone=public
firewall-cmd --reloadOptionally, route all dhcpd logs to a dedicated log file
bash -c "cat > /etc/rsyslog.d/50-dhcpd.conf"<<'EOF'
# Log dhcpd log messages to file
if $programname == 'dhcpd' then /var/log/dhcpd.log
EOFRestart rsyslog
systemctl restart rsyslog.service