# Raspberry Pi DHCP Server

* Install network-manager

sudo apt-get install network-manager

* Enable network-manager

sudo service network-manager start

* Set up wifi wan

nmcli dev
nmcli radio wifi on
nmcli dev wifi list
sudo nmcli dev wifi connect "network-ssid" password "network-password" 

* if you can't find out the wifi list, you should try the way like the following
* Edit the yaml file and delete the content and save.

sudo vim /etc/netplan/50-cloud-init.yaml

* Edit the NetworkManager.conf

cd /etc/NetworkManager/
vim NetworkManager.conf

* Make the managed = true

cd conf.d/
ls

* Add file named '10-globally-managed-devices.conf' and the content is 'unmanaged-devices=none'
* Then restart the NetworkManager

sudo systemctl restart NetworkManager
netplan apply

* Create a bridge interface named 'brVLAN1' and the network interface card is brVLAN1 and the interface type is bridge

sudo nmcli con add ifname brVLAN1 type bridge con-name brVLAN1
nmcli connection show

* Create a bridge interface named 'brVLAN2' by **OVS**

sudo ovs-vsctl add-br brVLAN2

* If occur error, you should delete the ${connect_name} like 'bridge-slave-x'

nmcli connection delete <CONNECTION_NAME>

* And readd the bridge

nmcli con add type bridge-slave ifname eth0 master brVLAN1

* Add LAN port to 'brVLAN1'
* ${x} is mean the connect LAN port like 'eth0'

nmcli con add type bridge-slave ifname ${x} master brVLAN1

* Add LAN port to 'brVLAN2' by **OVS**

ovs-vsctl add-port brVLAN2 eth0

* Install DHCP Server

apt install isc-dhcp-server

* Install iptables-persistent

sudo apt-get install iptables-persistent

* Set up DHCP Server

sudo vim /etc/dhcp/dhcpd.conf

* Add Ip Address to 'brVLAN1'

sudo nmcli connection modify brVLAN1 ipv4.addresses '192.168.0.1/24'
sudo nmcli con modify brVLAN1 ipv4.method manual
sudo nmcli con up brVLAN1 

* Add Ip Address to 'brVLAN2' by OVS

ip addr add 192.168.0.1/24 dev brVLAN2
ifconfig brVLAN2 up
vim /etc/default/isc-dhcp-server

* Check the status of DHCP Server

systemctl status isc-dhcp-server

* The content of dhcpd.conf

option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;
default-lease-time 600;
max-lease-time 7200;
ddns-update-style none;
authoritative;
subnet 192.168.0.0 netmask 255.255.255.0{
    range 192.168.0.2 192.168.0.254;
    option routers 192.168.0.1;
    option subnet-mask 255.255.255.0;
    option broadcast-address 192.168.0.255;
    option domain-name-servers 8.8.8.8;
    default-lease-time 3600;
    max-lease-time 7200;
}

* Restart DHCP Server setting

sudo systemctl restart isc-dhcp-server

* Iptables clean

# flush all chains
iptables -F
iptables -t nat -F
iptables -t mangle -F
# delete all chains
iptables -X

* Add the rules of Nat
* 'x.x.x.x/24' is mean the network segment like '192.168.0.0/24'

iptables -t nat -A POSTROUTING -s x.x.x.x/24 -o wlan0 -j MASQUERADE
sudo vim /etc/sysctl.conf
add "net.ipv4.ip_forward=1"
sudo sysctl -p

* Save iptables setting

sudo dpkg-reconfigure iptables-persistent