Would you like to use your Pi as a WiFi router? Or maybe have it as a special filtering access point? Setting up a Pi as an access point (AP) is a bit more advanced than using it as a client, but its still only a half hour of typing to configure. If you want to, this tutorial will make it so the Pi broadcasts a WiFi service and then routes internet traffic to an Ethernet cable. Since its all Linux you can go in and update or configure it however you like.
I used the following pages as a guide to create this tutorial,
please note many of them will not work completely, but check them out if you are interested!
- http://qcktech.blogspot.com/2012/08/raspberry-pi-as-router.html
- http://itsacleanmachine.blogspot.com/2013/02/wifi-access-point-with-raspberry-pi.html
- http://esrlabs.com/android-transporter-for-the-nexus-7-and-the-raspberry-pi/
- http://elinux.org/RPI-Wireless-Hotspot
Currently tested working on Raspbian only
You'll need a few things to run this tutorial:
- Raspberry Pi model B - Ethernet is required
- Ethernet cable
- WiFi adapter - Not all WiFi adapters work, we know for sure it works with the ones in the Adafruit shop!
- SD Card (4GB or greater) with Raspbian on it. You can either DIY it or buy a ready-made Raspbian card
- Power supply for your Pi & a Micro USB cable
- USB Console cable (optional) - this makes it a little easier to debug the system
- Case for your Pi (optional)
- A SD or MicroSD card reader (optional)
Our Pi starter pack + a Wifi adapter will be all you need and even comes with more fun stuff you can play with
This tutorial assumes you have your Pi mostly set up and ready to go.
Please follow the tutorials in order to
- Install the OS onto your SD card
- Boot the Pi and configure
Don't forget to change the default password for the 'pi' acccount!
- Set up and test the Ethernet and Wifi connection
- Connect with a USB console cable (optional)
When done you should have a Pi that is booting Raspbian, you can connect to with a USB console cable and log into the Pi via the command line interface.
It is possible to do this tutorial via
ssh on the Ethernet port
or using a console cable.
If using a console cable, even though the diagram on the last step shows powering the Pi via the USB console cable (red wire) we suggest not connecting the red wire and instead powering from the wall adapter. Keep the black, white and green cables connected as is.
Don't forget to expand the SD card, or you may run out of space!
Before continuing make sure the Ethernet cable is connected in and you can
ping out from the Pi
You will also want to set up your WiFi dongle. run
sudo shutdown -h now
and then plug in the WiFi module when the Pi is off so you don't cause a power surge.
When it comes back up check with
ifconfig -a
that you see
wlan0 - the WiFi module.
Next up we install the software onto the Pi that will act as the 'hostap' (host access point)
You need internet access for this step so make sure that Ethernet connection is up!
sudo apt-get install hostapd isc-dhcp-server
(You may need to
sudo apt-get update if the Pi can't seem to get to the apt-get repositories)
(text above shows udhcpd but that doesnt work as well as isc-dhcp-server, still, the output should look similar)
Set up DHCP server
Next we will edit /etc/dhcp/dhcpd.conf, a file that sets up our DHCP server - this allows wifi connections to automatically get IP addresses, DNS, etc.
Run this command to edit the file
sudo nano /etc/dhcp/dhcpd.conf
Find the lines that say
option domain-name "example.org";
option domain-name-servers ns1.example.org, ns2.example.org;
and change them to add a # in the beginning so they say
#option domain-name "example.org";
#option domain-name-servers ns1.example.org, ns2.example.org;
Find the lines that say
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
#authoritative;
and remove the # so it says
# If this DHCP server is the official DHCP server for the local
# network, the authoritative directive should be uncommented.
authoritative;
Then scroll down to the bottom and add the following lines
- subnet 192.168.42.0 netmask 255.255.255.0 {
- range 192.168.42.10 192.168.42.50;
- option broadcast-address 192.168.42.255;
- option routers 192.168.42.1;
- default-lease-time 600;
- max-lease-time 7200;
- option domain-name "local";
- option domain-name-servers 8.8.8.8, 8.8.4.4;
- }
Save the file by typing in
Control-X then
Y then
return
Run
sudo nano /etc/default/isc-dhcp-server
and scroll down to
INTERFACES="" and update it to say
INTERFACES="wlan0"
Set up wlan0 for static IP
If you happen to have
wlan0 active because you set it up, run
sudo ifdown wlan0
There's no harm in running it if you're not sure
Next we will set up the
wlan0 connection to be static and incoming. run
sudo nano /etc/network/interfaces to edit the file
Find the line
auto wlan0 and add a
# in front of the line, and in front of every line afterwards. If you don't have that line, just make sure it looks like the screenshot below in the end! Basically just remove any old
wlan0configuration settings, we'll be changing them up
Depending on your existing setup/distribution there might be more or less text and it may vary a little bit
Add the lines
- iface wlan0 inet static
- address 192.168.42.1
- netmask 255.255.255.0
After
allow hotplug wlan0 - see below for an example of what it should look like. (ignore our hyphen in allow-hotplug tho, its a typo!) Any other lines afterwards should have a
# in front to disable them
Save the file (Control-X Y <return>)
Assign a static IP address to the wifi adapter by running
sudo ifconfig wlan0 192.168.42.1
Configure Access Point
Now we can configure the access point details. We will set up a password-protected network so only people with the password can connect.
Create a new file by running
sudo nano /etc/hostapd/hostapd.conf
Paste the following in, you can change the text after
ssid= to another name, that will be the network broadcast name. The password can be changed with the text after
wpa_passphrase=
- interface=wlan0
- driver=rtl871xdrv
- ssid=Pi_AP
- hw_mode=g
- channel=6
- macaddr_acl=0
- auth_algs=1
- ignore_broadcast_ssid=0
- wpa=2
- wpa_passphrase=Raspberry
- wpa_key_mgmt=WPA-PSK
- wpa_pairwise=TKIP
- rsn_pairwise=CCMP
If you are not using the Adafruit wifi adapters, you may have to change the
driver=rtl871xdrv to say
driver=nl80211 or something, we don't have tutorial support for that tho, YMMV!
Save as usual. Make sure each line has no extra spaces or tabs at the end or beginning - this file is pretty picky!
Now we will tell the Pi where to find this configuration file. Run
sudo nano /etc/default/hostapd
Find the line
#DAEMON_CONF="" and edit it so it says
DAEMON_CONF="/etc/hostapd/hostapd.conf"
Don't forget to remove the
# in front to activate it!
Then save the file
Configure Network Address Translation(如果需要AP需要上网则需要这步)
Setting up NAT will allow multiple clients to connect to the WiFi and have all the data 'tunneled' through the single Ethernet IP. (But you should do it even if only one client is going to connect)
Run
sudo nano /etc/sysctl.conf
Scroll to the bottom and add
net.ipv4.ip_forward=1
on a new line. Save the file. This will start IP forwarding on boot up
Also run
sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward
"
to activate it immediately
Run the following commands to create the network translation between the ethernet port
eth0 and the wifi port
wlan0
- sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
- sudo iptables -A FORWARD -i eth0 -o wlan0 -m state --state RELATED,ESTABLISHED -j ACCEPT
- sudo iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT
You can check to see whats in the tables with
sudo iptables -t nat -S
sudo iptables -S
To make this happen on reboot (so you don't have to type it every time) run
sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"
run
sudo nano /etc/network/interfaces and add
up iptables-restore < /etc/iptables.ipv4.nat
to the very end
Update hostapd(上面的hostapd为x86架构的，如果在Pi上使用需要换为ARM架构)
Before we can run the access point software, we have to update it to a version that supports the WiFi adapter.
First get the new version by typing in
wget
http://www.adafruit.com/downloads/adafruit_hostapd.zip
to download the new version (check the next section for how to compile your own updated
hostapd) then
unzip adafruit_hostapd.zip
to uncompress it. Move the old version out of the way with
sudo mv /usr/sbin/hostapd /usr/sbin/hostapd.ORIG
And move the new version back with
sudo mv hostapd /usr/sbin
set it up so its valid to run with
sudo chmod 755 /usr/sbin/hostapd
First test!
Finally we can test the access point host! Run
sudo /usr/sbin/hostapd /etc/hostapd/hostapd.conf
To manually run
hostapd with our configuration file. You should see it set up and use
wlan0 then you can check with another wifi computer that you see your SSID show up. If so, you have successfully set up the access point.
If you get an INVALID ARGUMENT warning from hostapd, you may need to compile your own version of hostapd - there's instructions here http://forums.adafruit.com/viewtopic.php?f=19&t=47716#p240781
You can try connecting and disconnecting from the Pi_AP, debug text will display on the Pi console but you won't be able to connect through to the Ethernet connection yet.
Cancel the test by typing
Control-C in the Pi console to get back to the Pi command line
Finishing up!
OK now that we know it works, time to set it up as a 'daemon' - a program that will start when the Pi boots.
Run the following commands
sudo service hostapd start
sudo service isc-dhcp-server start
you can always check the status of the host AP server and the DHCP server with
sudo service hostapd status
sudo service isc-dhcp-server status
To start the daemon services. Verify that they both start successfully (no 'failure' or 'errors')
Then to make it so it runs every time on boot
sudo update-rc.d hostapd enable
sudo update-rc.d
isc-dhcp-server enable
Extra: Removing WPA-Supplicant
Depending on your distro, you
may need to remove WPASupplicant. Do so by running this command:
sudo mv /usr/share/dbus-1/system-services/fi.epitest.hostap.WPASupplicant.service ~/
and then rebooting (
sudo reboot)
Now that we have the software installed on a Pi, it's time to connect to it and test the connection. I'm using a Windows computer but any kind should work fine
On the Pi, run the command
tail -f /var/log/syslog to watch the system log data, handy for checking and debugging whats going on!
Connect with another computer to the AP you made in the previous step
Enter the WPA key you specified in the previous step
In the Pi syslog you should see stuff like this! It indicates that a client connected, at what time and what IP address was given to them
If you can't connect at all, something is wrong with
hostapd
On your computer, open up a
Terminal (mac/linux) or
Start->Run->cmd to open up a command line
First check what
ifconfig (mac/linux) or
ipconfig (windows) says. You should have IP address in the 192.168.42.10-50 range
Try pinging the Pi, its address is 192.168.42.1 - on windows it will ping 3 times and quit. On mac/linux press Control-C to quit after a few pings. You should get successful pings as seen below
If that doesn't work, something is wrong with
hostapd or
dhcpd (more likely)
Next try pinging 8.8.8.8, if this doesn't work but the previous does, something is wrong with
dhcpd or the NAT configuration (more likely)
Finally, we'll check that DNS works, try pinging www.mit.edu. If this doesn't work, something is wrong with
dhcpd
If everything is good so far, try browsing the internet, sending email, etc. You are now using your Pi as a Wifi Router!
More!
Its possible to set up your router for open or WEP access, but we don't cover that here (and it's not as secure!) You might want to search around for tutorials such as this one that cover
hostapd options
You may have noticed that one step is downloading a copy of hostapd from adafruit.com and swapping it with yours. In case you want to compile your own, here's how (its easy but not necessary if you are OK with using our binary)
- Go to the Realtek downloads page http://152.104.125.41/downloads/downloadsView.aspx?Langid=1&PNid=21&PFid=48&Level=5&Conn=4&ProdID=27...
- Download linux 3.4.4_4749
- Copy the zip to the SD card using any computer which will place it in the Pi's /boot directory (or somehow get that file onto your Pi)
- Boot the Pi from the SD card
- sudo mv /boot/RTL8192xC_USB_linux_v3.4.4_4749.20121105.zip .
- unzip RTL8192xC_USB_linux_v3.4.4_4749.20121105.zip
- mv RTL8188C_8192C_USB_linux_v3.4.4_4749.20121105/ rtl
- cd rtl
- cd wpa_supplicant_hostapd
- unzip wpa_supplicant_hostapd-0.8_rtw_20120803.zip
- cd wpa_supplicant_hostapd-0.8/
- cd hostapd
- make
- *have a sandwich*
- when done, hostapd binary is in the directory
=========================================================================
转载自http://learn.adafruit.com/setting-up-a-raspberry-pi-as-a-wifi-access-point?view=all
