Setting up a wifi hotspot with brctl and hostapd

Question

I am trying to set up a wifi hotspot using brctl and hostapd on Debian GNU/Linux but it seems it does not work. The steps I follow are the following:

echo 1 > /proc/sys/net/ipv4/ip_forward
brctl addbr br0
brctl addif br0 eth0
dhclient br0

Until now it works and I am able to surf the web using the wired connection. Then, I launch hostapd. It adds wlan0 to the bridge and the wired conncetion stops to work: I am not able to surf the web and the smartphone (with Android) is able to authenticate with the hotspot but does not get an IP address and says "Limited conncetion".

I have read several guides and howtos but I cannot find a solution. Any suggestion?

Answer 1

There are a few key points to consider:

1. You must disable network manager:

   sudo service network-manager stop
   

2. You must start hostapd before the bridge:

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

3. Now you just add eth0 to an existing bridge:

   sudo brctl addif br0 eth0
   

4. and you put your bridge onto the network:

   sudo dhclient br0
   

5. Now you have to check that your routing table is working:

   sudo add -net 0.0.0.0/0 gw IP_address_of_your_router dev br0
   sudo del -net 0.0.0.0/0 gw IP_address_of_your_router dev eth0
   

6. Now you add nameservers to /etc/resolv.conf: as sudo,

   echo nameserver 8.8.8.8 >> /etc/resolv.conf
   echo nameserver 8.8.4.4 >> /etc/resolv.conf
   

Mine works as above: I am writing through it just now.

Answer 2

I ended up choosing another way to doing the same thing, based off the guide here - using /hosts/networks is probably better if you need an always on hostapd AP, but probably less use otherwise.

Here's my /etc/networks file - I've set wlan0 as manual , and bridged eth0.

# wireless wlan0
allow-hotplug wlan0
iface wlan0 inet manual

# eth0 connected to the ISP router
allow-hotplug eth0
iface eth0 inet manual
#iface eth0 inet6 auto
# Setup bridge
iface br0 inet static
    bridge_ports wlan0 eth0
    address 192.168.1.127
    netmask 255.255.255.0
    network 192.168.1.0
    gateway 192.168.1.1
    dns-nameservers 192.168.1.1

Your hostapd.conf might also be of interest there - this is a stripped down version of mine, since I chose to edit the 'stock' one. I suspect its pretty likely your problem might be there.

### Wireless network name ###
interface=wlan0
### Set your bridge name ###
bridge=br0
driver=nl80211

###CHANGE ANYTHING BELOW THIS TO SUIT!###

### (IN == INDIA, UK == United Kingdom, US == United Stats and so on ) ###
country_code=SG
hw_mode=g
channel=6
wpa=2
## Key management algorithms ##
wpa_key_mgmt=WPA-PSK

## Set cipher suites (encryption algorithms) ##
## TKIP = Temporal Key Integrity Protocol
## CCMP = AES in Counter mode with CBC-MAC
wpa_pairwise=TKIP
rsn_pairwise=CCMP

## Shared Key Authentication ##
auth_algs=1

## Accept all MAC address ###
macaddr_acl=0