Raspberry PI 3 AP

• We need to install dnsmasq and hostapd

sudo apt-get install dnsmasq hostapd

• Now edit the dhcpcd.conf file with

sudo nano /etc/dhcpcd.conf

and add the following line to the bottom of the file:

denyinterfaces wlan0

• Edit /etc/network/interfaces adding your own configuration

sudo nano /etc/network/interfaces

	allow-hotplug wlan0
	iface wlan0 inet static 
   address 10.0.20.201
    netmask 255.255.0.0
    network 10.0.20.200
    broadcast 10.0.20.255
    #wpa-conf /etc/wpa_supplicant/wpa_supplicant.conf

• restart service

sudo service dhcpcd restart
sudo ifdown wlan0 
sudo ifup wlan0

• edit the hostapd configuration file

sudo nano /etc/hostapd/hostapd.conf

• adding the following configuration

interface=wlan0
driver=nl80211
ssid=Pi3-AP
hw_mode=g
channel=6
ieee80211n=1
wmm_enabled=1
ht_capab=[HT40][SHORT-GI-20][DSSS_CCK-40]
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_key_mgmt=WPA-PSK
wpa_passphrase=raspberry
rsn_pairwise=CCMP

• check the configuration, a wifi network will be available

sudo /usr/sbin/hostapd /etc/hostapd/hostapd.conf

• press CTRL+C to exit, now edit the hostapd file with

sudo nano /etc/default/hostapd`

DAEMON_CONF="/etc/hostapd/hostapd.conf"

• Modify dnsmasq dns server

sudo mv /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
sudo nano /etc/dnsmasq.conf

• add the following configuration ( you have to modify according to your /etc/network/interfaces configuration

interface=wlan0      # Use interface wlan0  
listen-address=10.0.20.201 # Explicitly specify the address to listen on  
bind-interfaces      # Bind to the interface to make sure we aren't sending things elsewhere  
server=8.8.8.8       # Forward DNS requests to Google DNS  
domain-needed        # Don't forward short names  
bogus-priv           # Never forward addresses in the non-routed address spaces.  
dhcp-range=10.0.20.210,10.0.20.220,12h # Assign IP addresses between 10.0.20.210 and 10.0.20.220 with a 12 hour lease time  

• you can edit or remove dhcp-range ip lease time

• edit

sudo nano /etc/sysctl.conf

• remove the # from the beginning of the line containing net.ipv4.ip_forward=1

• add the following command

sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"
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
sudo sh -c "iptables-save > /etc/iptables.ipv4.nat"

• modify /etc/rc.local

sudo nano /etc/rc.local

• and just above the line exit 0, add the following line:

iptables-restore < /etc/iptables.ipv4.nat

sudo service hostapd start 
sudo service dnsmasq start  

• reboot your device

#enjoy :P