Raspberry Pi做成路由器

曾经看到很多文章把Raspberry Pi制作成无线AP，但是我今天要做的是把Raspberry Pi做成一个有NAT功能的路由器,我做这个的初衷是因为到荷兰出差后发现我的bambook无法接入宿舍里的WiFi，也许是因为宿舍无线路由器是WEP的认证方式，总之死活连不上。后来决定用Raspberry Pi+北极星光无线路由器来解决问题。Raspberry Pi 树莓派搭LAMP服务器 http://www.linuxidc.com/Linux/2013-06/86687.htm在树莓派Raspberry Pi上安装游戏模拟器 http://www.linuxidc.com/Linux/2013-07/86842.htmRaspberry Pi 树莓派上安装Weston http://www.linuxidc.com/Linux/2013-06/86685.htm用于Raspberry Pi 的Linux 操作系统已经可用 http://www.linuxidc.com/Linux/2012-03/56058.htmRaspberry Pi（树莓派）试用小记 http://www.linuxidc.com/Linux/2013-10/91008.htmRaspberry Pi（树莓派）的安装、配置IP及软件源等入门 http://www.linuxidc.com/Linux/2013-10/91009.htm思路：
【无线路由器】-----【无线网卡--Raspberry Pi--有线RJ45端口】------【有线RJ45端口--北极星光无线路由器--无线】----Bambook步骤一：
配置Raspberry Pi的无线网卡与有线网卡无线网卡通过WEP连到宿舍无线路由器，并配置一个固定IP，有线网卡也配置固定IPpi@raspberrypi:~$ cat /etc/network/interfaces
auto lo

iface lo inet loopback

iface eth0 inet static
address 172.16.1.100
netmask 255.255.255.0
gateway 172.16.1.1

#########################################
allow-hotplug wlan0
iface wlan0 inet static
#wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
#iface default inet dhcp
wireless-essid ADSL-WiFi-c91f44
wireless-key 1234567890
address 192.168.1.100
netmask 255.255.255.0
gateway 192.168.1.254步骤二：
在Raspberry Pi上架设DHCP服务器pi@raspberrypi:~$ sudo apt-get install isc-dhcp-server
编辑dhcp.conf文件pi@raspberrypi:~$ sudo vi /etc/dhcp/dhcpd.conf
在dhcp.conf文件的最后加上以下几行subnet 172.16.1.0 netmask 255.255.255.0 {
range 172.16.1.1 172.16.1.99;
option routers 172.16.1.100;
option domain-name-servers 8.8.8.8,8.8.4.4;
}
在Raspberry Pi的RJ45口上连上笔记本后测试是否可以分配IP地址pi@raspberrypi:~$ sudo service isc-dhcp-server restart
Stopping ISC DHCP server: dhcpd.
Starting ISC DHCP server: dhcpd.步骤三：启用Raspberry Pi的路由转发功能，并开启NAT开启路由转发功能pi@raspberrypi:~$ sudo vi /etc/sysctl.conf把sysctl.conf里的 net.ipv4.ip_forward=1前的"#"号去掉后保存开启NAT功能制作一个开启NAT的脚本，保存为nat#！/bin/sh
sudo iptables -t nat -A POSTROUTING -o wlan0 -j MASQUERADE
sudo iptables -A FORWARD -i wlan0 -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
sudo iptables -A FORWARD -i eth0 -o wlan0 -j ACCEPT
运行此脚本pi@raspberrypi:~$ ls | grep nat
nat
pi@raspberrypi:~$ sh ./nat
pi@raspberrypi:~$ sudo iptables -L
Chain INPUT （policy ACCEPT）
target prot opt source destination

Chain FORWARD （policy ACCEPT）
target prot opt source destination
ACCEPT all -- anywhere anywhere state RELATED,ESTABLISHED
ACCEPT all -- anywhere anywhere

Chain OUTPUT （policy ACCEPT）
target prot opt source destination
pi@raspberrypi:~$ sudo iptables -t nat -L
Chain PREROUTING （policy ACCEPT）
target prot opt source destination

Chain INPUT （policy ACCEPT）
target prot opt source destination

Chain OUTPUT （policy ACCEPT）
target prot opt source destination

Chain POSTROUTING （policy ACCEPT）
target prot opt source destination
MASQUERADE all -- anywhere anywhere
pi@raspberrypi:~$
在/etc/network/目录下创建一个iptables的文件pi@raspberrypi:~$ sudo touch /etc/network/iptables
把iptables内容保存到/etc/network/iptables中pi@raspberrypi:~$ sudo sh -c "iptables-save > /etc/network/iptables"
pi@raspberrypi:~$ cat /etc/network/iptables
# Generated by iptables-save v1.4.14 on Sun Jun 15 05:45:28 2014
*filter
:INPUT ACCEPT [22972:1979567]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [2421:275063]
-A FORWARD -i wlan0 -o eth0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -i eth0 -o wlan0 -j ACCEPT
COMMIT
# Completed on Sun Jun 15 05:45:28 2014
# Generated by iptables-save v1.4.14 on Sun Jun 15 05:45:28 2014
*nat
:PREROUTING ACCEPT [9719:1105033]
:INPUT ACCEPT [1273:238753]
:OUTPUT ACCEPT [675:88515]
:POSTROUTING ACCEPT [219:34192]
-A POSTROUTING -o wlan0 -j MASQUERADE
COMMIT
# Completed on Sun Jun 15 05:45:28 2014
pi@raspberrypi:~$在/etc/network/interfaces上加上一句up iptables-restore < /etc/network/iptables使得每次启动的时候自动生效pi@raspberrypi:~$ cat /etc/network/interfaces
auto lo

iface lo inet loopback

iface eth0 inet static
address 172.16.1.100
netmask 255.255.255.0
gateway 172.16.1.1

#########################################
allow-hotplug wlan0
iface wlan0 inet static
#wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
#iface default inet dhcp
wireless-essid ADSL-WiFi-c91f44
wireless-key 1234567890
address 192.168.1.100
netmask 255.255.255.0
gateway 192.168.1.254

up iptables-restore < /etc/network/iptables
保存重启发现连上Raspberry Pi的RJ45口的便携机能自动获取IP地址，并且可以ping通外网了。本文永久更新链接地址