automated Install wireguard script for Ubuntu 20.04

install_wireguard.sh

@!/usr/bin/env bash

set -xe

sudo apt update && sudo apt install -y wireguard

export CLIENT_PUBLIC_KEY="[INSERT CLIENT PUB KEY HERE]"
export CLIENT_VPN_IP="10.0.0.2" # change this if necessary, the server vpn ip is 10.0.0.1 as defined in the config

export SERVER_NAME="serverwg"
export INTERFACE_WG="wg0"

sudo mkdir -p /etc/wireguard/keys; 

wg genkey | sudo tee "/etc/wireguard/keys/${SERVER_NAME}.key" | \
    wg pubkey | sudo tee "/etc/wireguard/keys/${SERVER_NAME}.key.pub";

echo
echo "CREATING THE SERVER CONFIG"
echo

DEFAULT_INTERFACE="$(ip -o -4 route show to default | awk '{print $5}')"

PRIVATE_KEY=$(sudo cat /etc/wireguard/keys/beefy.key)

cat << EOF | sudo tee "/etc/wireguard/${INTERFACE_WG}.conf"
[Interface]
Address = 10.0.0.1/24
ListenPort = 51820
PrivateKey = ${PRIVATE_KEY}
PostUp = iptables -A FORWARD -i %i -j ACCEPT; iptables -t nat -A POSTROUTING -o ${DEFAULT_INTERFACE} -j MASQUERADE
PostDown = iptables -D FORWARD -i %i -j ACCEPT; iptables -t nat -D POSTROUTING -o ${DEFAULT_INTERFACE} -j MASQUERADE
SaveConfig = true
EOF

sudo chmod 600 "/etc/wireguard/${INTERFACE_WG}.conf" "/etc/wireguard/keys/${SERVER_NAME}.key"

echo
echo "ACTIVATING WIREGUARD SERVICE"
echo

sudo wg-quick up "${INTERFACE_WG}"

sudo wg show "${INTERFACE_WG}"

echo
echo "ENABLE WIREGUARD SERVICE AT BOOT" 
echo

sudo systemctl enable wg-quick@wg0

echo
echo "SETTING UP IP FORWARDING"
echo

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

sudo sysctl -p

echo
echo "ACTIVATING FIREWALL"
echo

sudo ufw allow 51820/udp

sudo ufw allow 22/udp # might want to keep ssh open ;-)

sudo ufw enable # this will prompt yes/no :(

sudo ufw status verbose

echo
echo "AUTHORIZE CLIENT"
echo

sudo wg set "${INTERFACE_WG}" peer "${CLIENT_PUBLIC_KEY}" allowed-ips "${CLIENT_VPN_IP}"

echo 
echo "SERVER PUBLIC KEY"
echo 
echo "copy it to your client's configuration"
echo

sudo wg show "${INTERFACE_WG}" public-key