How do I create a non-adhoc wifi hotspot?

Question

I want to use my desktop with a wired ethernet connection (eth0) to operate my "TP-LINK TL-WN722N" USB Wifi Adapter (wlan0) as a non-adhoc access point (so my android can connect to it). I've asked a few questions for improvements at the end...

After MUCH searching, I finally found a method that works with about 95% of what I want.

Dependencies:

 hostapd
 bridge-utils

I modified "/etc/network/interfaces" to contain:

 auto lo
 iface lo inet loopback

 auto eth0
 iface eth0 inet manual

 auto br0
 iface br0 inet dhcp
 bridge_ports eth0
 bridge_stp off
 bridge_fd 0
 bridge_maxwait 0

My "/etc/hostapd/hostapd.conf" (which I had to write myself) contains:

 ### Guts ###

 interface=wlan0
 bridge=br0
 driver=nl80211

 ### General ###

 ssid=____________________
 hw_mode=g
 channel=1

 ### Security ###

 macaddr_acl=0
 auth_algs=1
 ignore_broadcast_ssid=0     ## 0 visible # 1 hidden ##
 wpa=2
 wpa_passphrase=____________________
 wpa_key_mgmt=WPA-PSK
 wpa_pairwise=TKIP
 rsn_pairwise=CCMP

 ### Reference ###

 ## Created Tuesday, February 14, 2012 ## Ubuntu 11.10 ##

 # Hostapd Linux Documentation Page
 # http://linuxwireless.org/en/users/Documentation/hostapd

 # Creating a Network Bridge on Ubuntu (January 16th, 2011)
 # http://webserver.linuxportal.nl/?p=422

(I've edited out the security bits for this post)

All of that allows me to open up a Terminal and execute:

 sudo hostapd -B /etc/hostapd/hostapd.conf

to have a functioning access point that my droid and all other wifi devices can connect to.

Aside from sharing this method with others since info for this setup is so sparse; there are three problems I hope to fix:

1. This configuration deactivates network manager and all of its functions. When you click it, it gives a "device not managed" message. (not essential, but a bit annoying to me)
2. This method seems to have a very hard time assigning more than one IP address at a time. The first connected device works flawlessly, but subsequent devices may await an IP address.
3. I must use a terminal to turn on Wifi. (Ok for me, but not family friendly). I figured out how to make a launcher using gksu and a simple script if anyone needs one...

1. (Why can't network manager do this out-of-the-box??)

Thanks in advance! I hope all of this can help someone else; I've never written a tutorial before and know virtually nothing about networking...

Perhaps related to network bridge - without destroying network manager (among others).

Created using Ubuntu 11.10.

Answer 1

I'm not sure about how to do this without clobbering NM, but it is possible to run automatically at boot and get IP addresses to assign easily (at least I have managed this with the same wireless card). This requires the packages hostapd and dnsmasq (not dnsmasq-base)

/etc/hostapd/hostapd.conf:

interface=wlan0
driver=nl80211 # This works on my TL-WN722N

ssid=______

channel=6
hw_mode=g

auth_algs=1
wpa=3
wpa_passphrase=_____
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP CCMP
rsn_pairwise=CCMP

/etc/default/hostapd:

# Defaults for hostapd initscript
#
# See /usr/share/doc/hostapd/README.Debian for information about alternative
# methods of managing hostapd.
#
# Uncomment and set DAEMON_CONF to the absolute path of a hostapd configuration
# file and hostapd will be started during system boot. An example configuration
# file can be found at /usr/share/doc/hostapd/examples/hostapd.conf.gz
#
DAEMON_CONF="/etc/hostapd/hostapd.conf"

# Additional daemon options to be appended to hostapd command:-
#   -d   show more debug messages (-dd for even more)
#   -K   include key data in debug messages
#   -t   include timestamps in some debug messages
#
# Note that -B (daemon mode) and -P (pidfile) options are automatically
# configured by the init.d script and must not be added to DAEMON_OPTS.
#
#DAEMON_OPTS=""

/etc/dnsmasq.conf (diff against maintainer's version):

--- /etc/dnsmasq.conf.dpkg-dist 2011-09-20 00:28:30.000000000 +0100
+++ /etc/dnsmasq.conf   2012-02-13 21:03:03.713554612 +0000
@@ -82,7 +82,7 @@
 # specified interfaces (and the loopback) give the name of the
 # interface (eg eth0) here.
 # Repeat the line for more than one interface.
-#interface=
+interface=wlan0
 # Or you can specify which interface _not_ to listen on
 #except-interface=
 # Or which to listen on by address (remember to include 127.0.0.1 if
@@ -133,7 +133,7 @@
 # a lease time. If you have more than one network, you will need to
 # repeat this for each network on which you want to supply DHCP
 # service.
-#dhcp-range=192.168.0.50,192.168.0.150,12h
+dhcp-range=192.168.3.10,192.168.3.49,12h

 # This is an example of a DHCP range where the netmask is given. This
 # is needed for networks we reach the dnsmasq DHCP server via a relay

/etc/network/interfaces:

auto lo
iface lo inet loopback

auto wlan0
iface wlan0 inet static
    address 192.168.3.1/24
    broadcast 192.168.3.255

/etc/sysctl.conf patch (run sudo sysctl -p /etc/sysctl.conf after changing):

--- sysctl.conf 2012-05-14 18:06:57.514873009 +0100
+++ /etc/sysctl.conf    2012-05-14 18:09:27.122876525 +0100
@@ -25,7 +25,7 @@
 #net.ipv4.tcp_syncookies=1

 # Uncomment the next line to enable packet forwarding for IPv4
-#net.ipv4.ip_forward=1
+net.ipv4.ip_forward=1

 # Uncomment the next line to enable packet forwarding for IPv6
 #  Enabling this option disables Stateless Address Autoconfiguration

Finally, set up NAT in iptables:

sudo iptables -A FORWARD -o eth0 -i eth1 -s 192.168.0.0/24 -m conntrack --ctstate NEW -j ACCEPT
sudo iptables -A FORWARD -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
sudo iptables -A POSTROUTING -t nat -j MASQUERADE
sudo iptables-save | sudo tee /etc/iptables.sav

and add iptables-restore < /etc/iptables.sav above exit 0 in /etc/rc.local.

This setup was mostly implemented by reading this howto and staring at man pages scratching my head.

Answer 2

Great answer guys. Most trouble occurs because of the Broadcom drivers in HP Laptops atleast. After a lot of searching turned this up.If you have a broadcom network controller Check if your card is compatible with b43(link 1). If it is , awesome , keep reading. The default Broadcom sta driver (wl) will not support access point mode. So install b43 taking precautionary measure to be online by any means necessary. Turn it on using modprobe. Now follow instructions and try to set up access point.

I've finally got hostap working with this and the sweet part is My nokia phone can detect the wifi so created(It can detect anything,adhoc or not). Now i have to play around with your file and see if i can get my playbook to detect .

1. (linuxwireless.org/en/users/Drivers/b43)
2. (pclinuxos.com/forum/index.php?topic=91991.0)