Unable to assign IP address to client using udhcpd

Question

I'm trying to setup my Raspberry Pi3 as a WiFi hotspot. I've used three different sets of instructions after complete reloads and cannot get any of them to work. I can see the RP3 in my list of WiFi networks and can connect. However my tablet (Google Samsung ) does not get an IP assigned.

I don't know anything about the OS and thus don't have any idea on what to try to do to diagnose.

Additional Information

I loaded by Pi3 with the latest version of Raspian. Like with the message above the Pi3 was not assigning an IP.

I noticed tonight that I could connect to the internet via direct connect/cat5 but not WiFi.

Yesterday I was on with WifI but could not get an IP address assigned to me tablet. So i don't know what the issue is. Here is what i have setup.

1. Installed hostapd udhcpd
2. Configure DHCP (/etc/udhcpd.conf)

3. Changed /etc/default/udhcpd. New line = #DHCPD_ENABLED="no"
4. Ran sudo ifconfig wlan0 192.168.42.1

5. Added to the bottom of the file /etc/network/interfaces. Instructions were if the line "iface wlan0 inet dhcp" is not present, then add these lines to the bottom of the file.
   This line was not present in my file so I added:

6. Was supposed to comment out (#) the following lines in /etc/network/interfaces:

    allow-hotplug wlan0, 
    wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf, and 
    iface default inet manual.
   

   However I only changed the top line since it was the only one in my file (#allow-hotplug wlan0)

7. Configure /etc/hostapd/hostapd.conf

8. Changed /etc/default/hostapd line #DAEMON_CONF="" to DAEMON_CONF="/etc/hostapd/hostapd.conf"

9. Ran sudo sh -c "echo 1 > /proc/sys/net/ipv4/ip_forward"

10. Added the following line to the bottom of /etc/sysctl.conf:

     net.ipv4.ip_forward=1
    

11. Ran the following commands in this order

    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" 
    

12. Changed /etc/network/interfaces and added the following line to the bottom of the file:

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

13. Ran

    sudo service hostapd start 
    
    sudo service udhcpd start 
    

At this point I could see the Wireless network but the Pi3 never assigned an IP to my tablet. This was yesterday when the WiFi appeared to work. Today the WiFi does not appear to be working

Ran this just to finish

sudo update-rc.d hostapd enable 
sudo update-rc.d udhcpd enable

Answer 1

Do you have an active DHCPD on your Raspberry? If you have you should take a look into the configuration with:

vi /etc/dhcp/dhpd.conf

If you don't have a dynamic range set your tablet won't get an IP address.

Does your WiFi hotspot work if you use a different device (maybe a laptop)? If it's possible you could try setting a static IP address to your device so you could see if there's just a problem with your DHCP.

Answer 2

You are almost there, you have all the proper setup (from what I can see) that is needed for hostapd to be working. The issue is with the dhcp, by default the latest raspbian has dhcpcd installed on the OS. You will need to edit the file /etc/dhcpcd.conf and add the following line denyinterfaces wlan0 to the end. Afterwards, reboot and it should work properly. Another way to do this is :

sudo su
echo "denyinterfaces wlan0" >> /etc/dhcpcd.conf
reboot

Answer 3

I was able to get the Hotspot setup using the info from the following site. This was quite helpful and worked for me.

https://frillip.com/using-your-raspberry-pi-3-as-a-wifi-access-point-with-hostapd/