HOWTO: Setup software access point (WiFi router)

  1. Install additional packages

    dhcp sudo vim rfkill zd1211-firmware hostapd hostap-utils iw dnsmasq make zip unzip pkgfile gcc htop iptables

  2. Install hostapd that supports RTL8188CUS device

a) Download patched version of hostapd from

https://www.dropbox.com/s/fnz0au6nxe3lohy/hostapd-rtl8192cu-0.8-1-armv6h.pkg.tar.xz

b) Install patched version of hostapd with

pacman -U hostapd-rtl8192cu-0.8-1-armv6h.pkg.tar.xz

OR

a) Download Realtek driver for RTL8188CUS from

http://www.realtek.com.tw/downloads/downloadsView.aspx?Langid=1&PNid=21&PFid=48&Level=5&Conn=4&DownTypeID=3&GetDown=false

b) Extract files from archive

unzip RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911.zip

c) Change to given directory

cd RTL8188C_8192C_USB_linux_v4.0.2_9000.20130911/wpa_supplicant_hostapd

d) Extract hostapd files

tar -xzvf wpa_supplicant_hostapd-0.8_rtw_r7475.20130812.tar.gz

e) Change to given directory

cd wpa_supplicant_hostapd-0.8_rtw_r7475.20130812/hostapd

f) Compile hostapd with Realtek driver

sudo make
sudo make install

g) Copy hostapd files and set permissions

sudo mv hostapd /usr/sbin/hostapd
sudo chown root.root /usr/sbin/hostapd
sudo chmod 755 /usr/sbin/hostapd

  1. Edit /etc/hostapd/hostapd.conf

    ssid= wpa_passphrase= interface=wlan0 bridge=br0 auth_algs=3 channel=7 driver=rlt871xdrv hw_mode=g logger_stdout=-1 logger_stdout_level=2 max_num_sta=5 rsn_pairwise=CCMP wpa=2 wpa_key_mgmt=WPA-PSK wpa_pairwise=TKIP CCMP

  2. Enable hostapd.service to automatically start hostapd

    sudo systemctl enable hostapd.service sudo systemctl start hostapd.service

  3. Setup bridge with netctl. Copy example bridge configuration

    cp -rvf /etc/netctl/examples/bridge /etc/netctl/bridge

  4. Edit ‘/etc/netctl/bridge’

    Description=”RPi bridge connection” Interface=br0 Connection=bridge BindsToInterfaces=(eth0) IP=dhcp

  5. Start and enable newly created bridge profile

    sudo netctl start bridge sudo netctl status bridge sudo netctl enable bridge

  6. Setup Network Address Translation (NAT)

a) Assign static IPv4 address to interface connected to other machines (wlan0)

ip link set up dev wlan0
ip addr add 192.168.0.1/24 dev wlan0

TODO: Use netctl to have static IP assigned at boot

b) Enable packet forwarding

sysctl -a | grep forward      # check current packet forwarding settings
sysctl net.ipv4.ip_forward=1  # temporarily enable packet forwarding

OR

c) Edit ‘/etc/sysctl.d/30-ipforward.conf’ to enable packet forwarding permanently

net.ipv4.ip_forward=1
net.ipv6.conf.default.forwarding=1
net.ipv6.conf.all.forwarding=1

  1. Enable NAT with iptables

    iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE iptables -A FORWARD -i wlan0 -o eth0 -j ACCEPT iptables -A FORWARD -m conntrack –ctstate RELATED,ESTABLISHED -j ACCEPT

    TODO: Read iptables article to find out how to save the rule and apply it on boot

  2. Install and setup DHCP server

a) Edit configuration file /etc/dhcpd.conf to contain

# Use Google DNS, change to 139.96.30.100, if a local DNS server is installed
option domain-name-servers 8.8.8.8;
option subnet-mask 255.255.255.0;
option routers 139.96.30.100;
subnet 139.96.30.0 netmask 255.255.255.0 {
  range 139.96.30.150 139.96.30.250;
}

b) Start dhcpd daemon with ‘dhcpd4.service’ using ‘systemctl’. Enable its automatic start on boot.

sudo systemctl enable dhcpd4.service
sudo systemctl start  dhcpd4.service

https://wiki.archlinux.org/index.php/Software_Access_Point http://anarsoul.blogspot.com.es/2013/08/access-point-with-raspberry-pi-and.html https://wiki.archlinux.org/index.php/Bridge_with_netctl http://forums.adafruit.com/viewtopic.php?f=19&t=47716 https://wiki.archlinux.org/index.php/Internet_sharing https://wiki.archlinux.org/index.php/Dhcpd

Also useful: iw list, lsusb, iwconfig