Adding a network bridge with IP address under Linux

bridge.service

[Unit]
Description=Network Bridge
After=syslog.target network.target

[Service]
Type=onehot
ExecStart=/opt/bridge.sh

[Install]
WantedBy=multi-user.target

bridge.sh

#!/bin/bash
# Enable strict mode (http://redsymbol.net/articles/unofficial-bash-strict-mode/)
IFS=$'\n\t'
set -exuo pipefail

# Add bridge
brctl addbr br0

# Add interfaces
ip link set down enp2s0
ip link set down enp3s0
brctl addif br0 enp2s0
brctl addif br0 enp3s0

# Connect
ip link set up enp2s0
ip link set up enp3s0
ip link set up dev br0

# Assign IP address
ip addr add dev br0 10.0.0.10/24 broadcast 10.0.0.255
route add default gw 10.0.0.1 dev br0

# Allow the bridge in the firewall
iptables -A FORWARD -p all -i br-pi -j ACCEPT

# More information: https://wiki.archlinux.org/index.php/Network_bridge