1. Install Chrony & Stop the old time service

sudo apt-get update sudo apt-get install chrony -y sudo systemctl stop systemd-timesyncd sudo systemctl disable systemd-timesyncd sudo systemctl enable chrony

2. Write the "Boot Proof" Config

sudo bash -c 'cat > /etc/chrony/chrony.conf <<EOF

--- BOOT PROOF NTP SERVERS (IPs) ---

Google Public NTP (IPs solve the "1970" boot loop)

server 216.239.35.0 iburst server 216.239.35.4 iburst

Cloudflare Public NTP

server 162.159.200.1 iburst server 162.159.200.123 iburst

--- OFFICIAL FINNISH AUTHORITIES ---

VTT MIKES

server time.mikes.fi iburst server time1.mikes.fi iburst server time2.mikes.fi iburst

DNA & FUNET

server ntp.dnainternet.fi iburst server ntp.funet.fi iburst

--- CORE SETTINGS ---

driftfile /var/lib/chrony/chrony.drift makestep 1.0 3 rtcsync

--- ACCESS CONTROL ---

Allow local network to sync from this server

allow 10.0.0.0/8

Listen on all interfaces

bindcmdaddress 0.0.0.0

--- LOGGING ---

logdir /var/log/chrony EOF'

3. Restart Chrony to apply

sudo systemctl restart chrony

verify the sources

chronyc sources -v