---
# System prepended metadata

title: Linux 網路設定 筆記
tags: [Internet, Linux]

---

###### tags: `Linux` `Internet`

Linux 網路設定 筆記
===

## Keywords
- DHCP
    - citation: [DHCP-Study Area](http://www.study-area.org/network/network_dhcp.htm)

- LAN(Local Area Netowrk)
- WLAN(Wireless LAN)
- WAN(Wide Area Network)


## Instructions
- ```ifconfig```
- ```iwconfig```
- ```/etc/init.d/networking restart```
    - 重啟網路
- ```sudo ifdown wlan0```
    - 關閉wlan0
- ```sudo ifup wlan0```
    - 開啟wlan0
> [time=Wen, July 18, 2018]
- ```sudo iwlist scan```
    - 掃描網路
    - ```sudo iwlist wlan0 scan | grep ESSID```
        - 只顯示e ssid

## Setup Wi-Fi

- Step 1: ```sudo vi /etc/network/interfaces```
```
# lo
auto lo
iface lo inet loopback

# eth0
allow-hotplug eth0
iface eth0 inet dhcp


# wlan0
auto wlan0
allow-hotplug wlan0

iface wlan0 inet dhcp
        wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf
```

- Step 2: ```sudo vi etc/wpa_supplicant/wpa_supplicant.conf```
```
# allow all with cipher
network={
    ssid="your_ssid"
    psk="your_password"
    key_mgmt=WPA-PSK
    # 小心不要多加空格
}
```

### Explain    
- 下次開機自動偵測網路 (設定完要記得重開機)
```auto eth0``` ```auto wlan0```
- 允許熱拔插
```allow-hotplug eth0```
- DHCP (自動取得 IP)
```iface eth0 inet dhcp```
- Static
    ```
    iface eth0 inet static
        address 192.168.1.90
        netmask 255.255.255.0
        gateway 192.168.1.254
    ```

## 測試網路連線
```ping [wan address]```
- ex: ```ping google.com```

### Reference
[interfaces](https://manpages.debian.org/stretch/ifupdown/interfaces.5.en.html)
[SETTING WIFI UP VIA THE COMMAND LINE](https://www.raspberrypi.org/documentation/configuration/wireless/wireless-cli.md)