樹莓派建立無線熱點AP (方便直接連接遙控機器人/攝像頭)

硬件:

樹莓派Raspberry Pi 3b (內置WIFI, Stretch版)

1) 更新系統

sudo apt-get update
sudo apt-get upgrade

2) 安裝所有必需的軟件, 並首先關閉這些軟件

sudo apt-get install dnsmasq hostapd
sudo systemctl stop dnsmasq
sudo systemctl stop hostapd

3) 配置Pi的內置WIFI設備(wlan0)的靜態IP e.g. 192.168.10.1

sudo nano /etc/dhcpcd.conf

到文件的尾並添加:

interface wlan0
    static ip_address=192.168.10.1/24

重啓dhcpcd

sudo service dhcpcd restart

4) 配置DHCP服務器(dnsmasq), 默認情況下配置文件包含很多不需要的信息. 建議並編輯一個新的:

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig  
sudo nano /etc/dnsmasq.conf

添加:

interface=wlan0
  dhcp-range=192.168.10.2,192.168.10.20,255.255.255.0,24h

5) 配置hostapd (AP信息) 

sudo nano /etc/hostapd/hostapd.conf

添加: 

interface=wlan0
driver=nl80211
ssid=NETWORK_NAME
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=WIFI_PASSWORD
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP

NETWORK_NAME = 網絡名字, WIFI_PASSWORD = WIFI密碼

sudo nano /etc/default/hostapd

找到#DAEMON_CONF, 替換爲：

DAEMON_CONF="/etc/hostapd/hostapd.conf"

sudo systemctl start hostapd
sudo systemctl start dnsmasq

6) 添加路由和MASQUERADE

sudo nano /etc/sysctl.conf

刪除#

#net.ipv4.ip_forward=1

sudo iptables -t nat -A  POSTROUTING -o eth0 -j MASQUERADE
sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

sudo nano /etc/rc.local

在“exit 0”之上添加

iptables-restore < /etc/iptables.ipv4.nat

7) 重新啓動pi

reboot

8) 測試: 

用一臺電腦來搜索wifi並連接它，然後嘗試SSH

參考鏈接: https://www.raspberrypi.org/documentation/configuration/wireless/access-point.md