OS used to configure IPv6 forwarding is Ubuntu 24.04.
# /etc/ufw/before6.rules
# Append to end of file after last COMMIT line (for *filter target) :
cat <<EOF >> /etc/ufw/before6.rules
*nat
:PREROUTING ACCEPT [0:0]
-A PREROUTING -i eth0 -d 2a00::101 -j DNAT --to-destination fd44::101
COMMIT
EOF
## Configure ip forwarding
cat <<EOF >> /etc/sysctl.conf
# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1
# Uncomment the next line to enable packet forwarding for IPv6
# Enabling this option disables Stateless Address Autoconfiguration
# based on Router Advertisements for this host
net.ipv6.conf.all.forwarding=1
EOF
# Reconfigure sysctl
sysctl -p
# Enable UFW - to load Ipv6 NAT rule
ufw allow ssh
ufw enable
ufw reload