Make Your Ubuntu Box as your Personal WiFi Hotspot / Wifi Router
First of all, we have to be sure weather the wifi card supports host mode or master mode. While most of the wifi module support this , there is no guaranty that every card will have this feature.
To be sure, we can install iw package to check the wifi card does have master / host mode or not.
$ sudo apt-get install iwTyping the** __** above command in a terminal will install iw package. Now type the following in the terminal.
$ iw listThis shows the a full technical details of your wifi card. A sample output of the command is as follows.
Wiphy phy0
Band 1:
Capabilities: 0x11ce
HT20/HT40
SM Power Save disabled
RX HT40 SGI
TX STBC
RX STBC 1-stream
Max AMSDU length: 3839 bytes
DSSS/CCK HT40
Maximum RX AMPDU length 65535 bytes (exponent: 0x003)
Minimum RX AMPDU time spacing: 8 usec (0x06)
HT TX/RX MCS rate indexes supported: 0-15
Frequencies:
* 2412 MHz [1] (15.0 dBm)
* 2417 MHz [2] (15.0 dBm)
* 2422 MHz [3] (15.0 dBm)
* 2427 MHz [4] (15.0 dBm)
* 2432 MHz [5] (15.0 dBm)
* 2437 MHz [6] (15.0 dBm)
* 2442 MHz [7] (15.0 dBm)
* 2447 MHz [8] (15.0 dBm)
* 2452 MHz [9] (15.0 dBm)
* 2457 MHz [10] (15.0 dBm)
* 2462 MHz [11] (15.0 dBm)
* 2467 MHz [12] (15.0 dBm) (passive scanning)
* 2472 MHz [13] (15.0 dBm) (passive scanning)
* 2484 MHz [14] (15.0 dBm) (passive scanning)
Bitrates (non-HT):
* 1.0 Mbps
* 2.0 Mbps (short preamble supported)
* 5.5 Mbps (short preamble supported)
* 11.0 Mbps (short preamble supported)
* 6.0 Mbps
* 9.0 Mbps
* 12.0 Mbps
* 18.0 Mbps
* 24.0 Mbps
* 36.0 Mbps
* 48.0 Mbps
* 54.0 Mbps
max # scan SSIDs: 4
max scan IEs length: 2257 bytes
Coverage class: 0 (up to 0m)
Supported Ciphers:
* WEP40 (00-0f-ac:1)
* WEP104 (00-0f-ac:5)
* TKIP (00-0f-ac:2)
* CCMP (00-0f-ac:4)
* CMAC (00-0f-ac:6)
Available Antennas: TX 0x3 RX 0x3
Configured Antennas: TX 0x3 RX 0x3
Supported interface modes:
* IBSS
* managed
* AP
* AP/VLAN
* WDS
* monitor
* mesh point
* P2P-client
* P2P-GO
software interface modes (can always be added):
* AP/VLAN
* monitor
valid interface combinations:
* #{ managed, WDS, P2P-client } <= 2048, #{ AP, mesh point, P2P-GO } <= 8,
total <= 2048, #channels <= 1
Supported commands:
* new_interface
* set_interface
* new_key
* new_beacon
* new_station
* new_mpath
* set_mesh_params
* set_bss
* authenticate
* associate
* deauthenticate
* disassociate
* join_ibss
* join_mesh
* remain_on_channel
* set_tx_bitrate_mask
* action
* frame_wait_cancel
* set_wiphy_netns
* set_channel
* set_wds_peerNow look at the section “Supported interface mode ” . If the list contains AP or AP/VLAN , then your wifi card supports master mode or host mode and you can proceed with this guide.
Step 1:
We will use hostapd package to use the wifi card as router /access point.
$ sudo apt-get install hostapdAfter installing hostapd, we have to create or edit the hostapd configuration file which is located at /etc/hostapd/hostapd.conf .
$ sudo gedit /etc/hostapd/hostapd.confComment out all the existing entries and add the following lines.
interface=wlan0
driver=nl80211
ssid=your_ssid_name
hw_mode=g
auth_algs=1
wpa=2
wpa_passphrase=your_pass_phrase
wpa_pairwise=TKIP CCMP
wpa_key_mgmt=WPA-PSK
channel=1
rsn_pairwise=CCMP
Step 2:
We need to install a dhcp server and configure it for wlan0. I have noticed the default dhcp server (dhcp3) has issue with hostapd. So I just uninstalled the default dhcp client and installed dnsmasq . This is really awesome application. dnsmasq works as a server as well as a client. It is also very easy to configure.
$ sudo apt-get purge dhcpd
$ sudo apt-get install dnsmasqNow we will edit the default dnsmasq parameters in /etc/default/dnsmasq .
$ sudo gedit /etc/default/dnsmasqThe file should only contain the following.
DNSMASQ_OPTS=" -conf-file=/etc/dnsmasq.conf"
Save it .**** Now we will create a config file /etc/dnsmasq.conf so that it gives the ip address to clients which tries to connect to hosted wifi access point.
$ sudo gedit /etc/dnsmasq.confComment out all the existing entries add the following at the end of the file .
#interface=wlan0
#dhcp-range=192.168.0.2,192.168.0.127,12hSave it.
Step3:
We have now setted up every thing to make our ubuntu box as wifi access point / wifi router.
Now we will create an executable script say /usr/bin/wifi_ap so that we can run it as a command.
Add the following lines in /usr/bin/wifi_ap .
#!/bin/bash
# broadcasting interface
BROADCAST="wlan0"
BROADCASTIP="192.168.0.1"
# receiving interface broadcast is connected to.
# put the correct interface name here. It is the network interface
# which is connected to internet and whose connection is going to be
#shared over wifi. E.g for internal 3g slot it is "hso0" , for ethernet it is
#"eth0", for ppp it is "ppp0"
#For me it is an internal 3g slot .
RECEIVE="hso0"
if [[ $1 == "-0" || $1 == "--start" ]]
then
## start hostapd
echo "Starting hostapd"
echo "You can view the log at /var/log/hostapd.log"
sleep 1
# launch hostapd daemon
hostapd -d /etc/hostapd/hostapd.conf > /var/log/hostapd.log &
echo "hostapd started.."
## start dhcp server; We are making sure that currently dnsmasq is not
#running by any other application. So before starting dnsmasq, we are
#trying to stop any previous session.
echo "Stopping previous dhcp session"
/etc/init.d/dnsmasq stop
killall -2 dnsmasq
echo "Starting dnsmasq DHCP Server on wlan0"
# set IP address
ifconfig $BROADCAST $BROADCASTIP
sleep 2
# launch dnsmasq dhcp daemon
#echo "INTERFACES=$BROADCAST" > /etc/default/dhcp
dnsmasq --conf-file=/etc/dnsmasq.conf
sleep 1
echo "DHCP Server Started..."
elif [[ $1 == "-1" || $1 == "--stop" ]]
then
# send signal 2 to hostapd and dnsmasq
echo "Stopping DHCP Server..."
sleep 1
/etc/init.d/dnsmasq stop
echo "DHCP server stopped..."
sleep 1
echo "Killing hostapd, dnsmasq"
killall -2 hostapd dnsmasq
sleep 1
echo "All process killed.."
elif [[ $1 == "-2" || $1 == "--ics" ]]
then
echo "Starting Internet connection sharing..."
# create iptables rules
iptables -A FORWARD -i $RECEIVE -o $BROADCAST -s 192.168.0.1/24 -m conntrack --ctstate NEW -j ACCEPT
iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
iptables -A POSTROUTING -t nat -j MASQUERADE
# set kernel variable(s)
echo 1 > /proc/sys/net/ipv4/conf/all/forwarding
# edit kernel configuration
cp /etc/sysctl.conf /etc/sysctl.conf.ap_ctl
echo "net.ipv4.conf.default.forwarding=1" >> /etc/sysctl.conf
echo "net.ipv4.conf.all.forwarding=1" >> /etc/sysctl.conf
sleep 1
echo "Internet connection is now shared over wifi..."
echo ""
# To stop internet sharing
elif [[ $1 == "-3" || $1 == "--noics" ]]
then
echo "Stopping Internet connection sharing..."
# remove iptables rules
iptables -D FORWARD 1
iptables -D FORWARD 1
# set kernel variable(s)
echo 0 > /proc/sys/net/ipv4/conf/all/forwarding
# revert kernel configuration
mv -i /etc/sysctl.conf.ap_ctl /etc/sysctl.conf
# restart networking
#/etc/init.d/networking restart
sleep 1
echo "Internet connection sharing stopped..."
else
echo $0
echo "A tool to manage hostapd and dnsmasq DHCP server"
echo "Usage:"
echo " -0 --start Start hostapd and dhcpd3"
echo " -1 --stop Stop hostapd and dhcpd3 with signal 2"
echo " -2 --ics Activate internet connection sharing"
echo " between specified interfaces"
echo " -3 --noics Undo internet connection sharing settings"
fi
exit 0
Save it. Exit the text editor. Now run
$ sudo chmod a+x /usr/bin/wifi_apNow you can run this script as command. This script has 4 options i.e start , stop , ics and noics .
To start the hostspot , you should run
$ sudo wifi_ap --startTo stop the hostspot , you can run
$ sudo wifi_ap --stopTo share internet connection over the hostspot
$ sudo wifi_ap --icsTo stop sharing internet connection ,
$ sudo wifi_ap --noics. Hope you will enjoy it.
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