basic LAN to WAN NAT in Ubuntu 24.04

sudo su -

vi /etc/netplan/50-cloud-init.yaml

network:
    ethernets:
        enp2s0:
            dhcp4: true
        enp3s0:
            addresses:
            - 10.0.0.0/24
    version: 2

grep DEFAULT_FORWARD_POLICY /etc/default/ufw
sed -i 's/DEFAULT_FORWARD_POLICY="DROP"/DEFAULT_FORWARD_POLICY="ACCEPT"/' /etc/default/ufw
grep DEFAULT_FORWARD_POLICY /etc/default/ufw

grep 'net.ipv4.ip_forward=1' /etc/sysctl.conf
sed -i 's/#net.ipv4.ip_forward=1/net.ipv4.ip_forward=1/' /etc/sysctl.conf
grep 'net.ipv4.ip_forward=1' /etc/sysctl.conf

vi /etc/ufw/before.rules 

*nat
:POSTROUTING ACCEPT [0:0]
# Allow traffic from OpenVPN client to eth0 (change to the interface you discovered!)
-A POSTROUTING -s 10.0.0.0/24 -o enp2s0 -j MASQUERADE
COMMIT

ufw allow from 10.0.0.0/24
ufw allow 22/tcp
ufw disable; ufw enable