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Switch Raspberry Hotspot "RaspAP" (wlan0) to a simple Wifi Device via a script

What is missing

    #!/bin/bash

    # This script will stop the RASPAP Hotspot (AP+DHP) and will Switch your Raspberry to a WIFI Client
    # Be care : Before to do that, be sure that you have the correct SSID in : wpa_supplicant.conf

    # Run : bash sap2cl.sh

    # First :
    # sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
    #
    #       ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
    #       update_config=1
    #       country=FR
    #       network={
    #        ssid="Freebox-CKL-I"
    #        psk="xxxxxxxxx"
    #       }

    echo "Stopping hostapd, dnsmasq & dhcpcd"
    sudo systemctl stop hostapd.service
    sudo systemctl stop dnsmasq.service
    sudo systemctl stop dhcpcd.service

    echo "Restart wpa_supplicant"
    sudo wpa_supplicant -B -Dnl80211,wext -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0

    echo "Done."
    exit

Nothing happen, after running the script : I can't find the IP address of my Raspberry through a network scanner

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3
  • If you search this site you will find a few posts with similar objectives. I even posted one which didn't require restart - which kind of worked. Whether any of them work is doubtful. Your idea is unlikely to work because it fails to understand how dhcpcd works. I believe it may be possible with systemd.networkd but this requires totally different setup.
    – Milliways
    Commented Mar 9, 2022 at 10:30
  • So I have certainly to start from the beginning, and not necessarily use RASPAP, but hostapd configuration that makes it easier to switch from client mode to Routed Wireless Access Point mode..
    – Christian Klugesherz
    Commented Mar 9, 2022 at 11:05
  • You can try to remove -B and add -d in wpa_supplicant command line to see debug lines. Also, wpa_supplicant not assign an IP address you must use dhclient. dhclient --help and in /etc/dhcp/dhclient.conf you can find config example. 1) start wpa_supplicant with & at the end or add -B, 2) start dhclient. NOTE: also you can create one second wireless interface ` iw dev wlan0 interface add ap0 type __ap` , one for the client (for wpa_supplicant, wlan0), one for the AP (for hostapd, ap0)
    – Ephemeral
    Commented Mar 9, 2022 at 13:59

3 Answers 3

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Was just having a look through this thread. I created a project a few years ago and wanted to find what has been discussed above, but rather than switching every reboot, I wanted it to connect to the local network if it found it, and if not (when I was out in the field), revert to ad-hoc.(where I could use it as a standalone webserver). I actually found this on another project it has been pretty useful to me, if that is what you need, (and like me, can't code, only follow instructions!) :)

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  • While this link may answer the question, it is better to include the essential parts of the answer here and provide the link for reference. Link-only answers can become invalid if the linked page changes. - From Review
    – Chenmunka
    Commented Oct 15, 2023 at 20:24
0

Finally I got the solution. The only point is that I need a reboot to switch from Client to AP. But this is not really an issue in my case. However if there could be a solution in the last script I'm openminded

See script : scl2ap.sh

Thanks

Wifi

Activate Wifi in /etc/wpa_supplicant/wpa_supplicant.conf

    ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
    update_config=1
    country=FR
    network={
        ssid="Freebox-CKL-I"
        psk="xxxxxxxxx"
    }

Kill and restart Wifi

sudo pkill wpa_supplicant
sudo wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0 -B -Dnl80211,wext

Access point:

The Raspberry Pi needs to have the hostapd access point software package installed:

sudo apt-get install hostapd

To create a new configuration file : /etc/hostapd/hostapd.conf Change : country, ssid , wpa_passphrase : to match with yours

    country_code=FR
    interface=wlan0
    ssid=LapemNetwork
    hw_mode=g
    channel=7
    macaddr_acl=0
    auth_algs=1
    ignore_broadcast_ssid=0
    wpa=2
    wpa_passphrase=password
    wpa_key_mgmt=WPA-PSK
    wpa_pairwise=TKIP
    rsn_pairwise=CCMP

Verify that configuration file location in /etc/init.d/hostapd containing is there, if not add. DAEMON_CONF=/etc/hostapd/hostapd.conf

Enable the wireless access point service and set it to start when your Raspberry Pi boots:

sudo systemctl unmask hostapd
sudo systemctl enable hostapd

DHCP Distribution

In order to provide network management services (DNS, DHCP) to wireless clients install dnsmasq

sudo apt-get install dnsmasq

To configure the distribution DHCP IP range we need to configure /etc/dnsmasq.conf At the bottom of the file we need to add the following lines.

    interface=wlan0
    dhcp-range=192.168.0.100,192.168.0.200,12h

activate the dnsmasq service at boot: sudo systemctl enable dnsmasq.service

AP as static

AP needs to have a static address: configured in etc/dhcpcd.conf

Defaut (DHCP) sudo cp /etc/dhcpcd.conf /etc/dhcpcd-dynamic.conf

Static add at the end of the file sudo nano /etc/dhcpcd.conf

    #Static IP
    interface wlan0
        static ip_address=192.168.0.1/24
        nohook wpa_supplicant


sudo cp  /etc/dhcpcd.conf /etc/dhcpcd-static.conf

Default mode AP

Command to run to activate AP for next boot

sudo systemctl unmask hostapd
sudo systemctl enable hostapd
sudo systemctl enable dnsmasq.service
sudo cp  /etc/dhcpcd-static.conf /etc/dhcpcd.conf

SWITCH : AP --> Client : definive

file : sap2cl.sh

Effect is dynamic and definive --> Next start will be as Client mode

#!/bin/bash
# This script will stop Hotspot (AP+DHCP) and will Switch your Raspberry to a WIFI Client (Definitely) 
# Effect is dynamic and definive --> Next start will be as Client mode
# Run : bash sap2cl.sh

echo "========================================"
echo " Switch from Hotspot (AP+DHP) to Client "
echo "  Next start will be : Wifi Client mode "
echo "========================================"
echo " "
echo "Stopping hostapd, dnsmasq "
sudo systemctl stop hostapd.service
sudo systemctl stop dnsmasq.service

echo "Configure Client to recover dhcp"
sudo cp  /etc/dhcpcd-dynamic.conf /etc/dhcpcd.conf
sudo systemctl daemon-reload

echo "Restart wpa_supplicant"
sudo pkill wpa_supplicant
sleep 2
sudo wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0 -B -Dnl80211,wext

echo "Done."
exit

SWITCH : AP --> Client : Next boot will be as AP

file : sap2clnsap.sh

Effect is dynamic --> Next start will be as AP

#!/bin/bash
# This script will stop Hotspot (AP+DHCP) and will Switch your Raspberry to a WIFI Client (Temporarily) 
# Effect is dynamic --> Next start will be as AP
# Run : bash sap2cl.sh

echo "========================================"
echo " Switch from Hotspot (AP+DHP) to Client "
echo "  Next start will be : AP mode "
echo "========================================"
echo " "
echo "Stopping hostapd, dnsmasq "
sudo systemctl stop hostapd.service
sudo systemctl stop dnsmasq.service

echo "Configure Client to recover dhcp"
sudo cp  /etc/dhcpcd-dynamic.conf /etc/dhcpcd.conf
sudo systemctl daemon-reload

echo "Restart wpa_supplicant"
sudo pkill wpa_supplicant
sleep 2
sudo wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0 -B -Dnl80211,wext

echo "Prepare for next start as AP"
sudo systemctl unmask hostapd
sudo systemctl enable hostapd
sudo systemctl enable dnsmasq.service
sudo cp  /etc/dhcpcd-static.conf /etc/dhcpcd.conf

echo "Done."
exit

SWITCH : Client --> AP : THIS IS NOT DYNAMIC, AND NEEDS A REBOOT

File : scl2ap.sh

#!/bin/bash
# This script will Switch from Client to Hotspot (AP+DHP) 
# Run : bash scl2ap.sh

echo "========================================="
echo " Switch from Client to Hotspot (AP+DHP)  "
echo " THIS IS NOT DYNAMIC, AND NEEDS A REBOOT "
echo "========================================="
echo " "
echo "Start hostapd, dnsmasq"

sudo systemctl restart dnsmasq.service
sudo systemctl restart hostapd.service

echo "Configure AP wit static IP Address"
sudo cp  /etc/dhcpcd-static.conf /etc/dhcpcd.conf
sudo systemctl daemon-reload

echo "Restart wpa_supplicant"
sudo pkill wpa_supplicant
sleep 2
sudo wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0 -B -Dnl80211,wext

echo "A REBOOT is needed here"
sudo systemctl unmask hostapd
sudo systemctl enable hostapd
sudo systemctl enable dnsmasq.service

echo "Done."
exit
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0

I am successfully switching between Client- AP mode without rebooting my raspberry pi4. I have 3 saved configurations, one for each client and AP mode: hostapd.conf, dnsmasq.conf, dhcpcd.conf

Client to AP:

sudo systemctl stop dnsmasq.service
sudo systemctl stop hostapd.service
echo "Configure AP wit static IP Address"
sudo cp -f /etc/hostapd/hostapd.conf.ap /etc/hostapd/hostapd.conf
sudo cp -f  /etc/dnsmasq.conf.ap /etc/dnsmasq.conf
sudo cp -f /etc/dhcpcd.conf.ap /etc/dhcpcd.conf
sudo systemctl daemon-reload
sudo pkill wpa_supplicant
sleep 2
sudo systemctl start dnsmasq.service
sudo systemctl start hostapd.service

AP to Client:

echo "Configure Client to recover dhcp"
sudo cp -f /etc/dnsmasq.conf.orig /etc/dnsmasq.conf
sudo cp  -f /etc/dhcpcd.conf.orig /etc/dhcpcd.conf
sudo systemctl daemon-reload

echo "Stopping  wpa_supplicant"
sudo pkill wpa_supplicant
sleep 2

sudo systemctl start hostapd.service
sudo wpa_supplicant -c/etc/wpa_supplicant/wpa_supplicant.conf -iwlan0 -B -Dnl80211,wext
sleep 5

And this is the script to setup the AP mode; run it only once to create the new configuration files. First, backup the original configuration files:

sudo apt-get install dnsmasq hostapd 
sudo cp -f /etc/dhcpcd.conf /etc/dhcpcd.conf.orig
sudo cp -f /etc/dnsmasq.conf /etc/dnsmasq.conf.orig
sudo cp -f /etc/hostapd/hostapd.conf /etc/hostapd/hostapd.conf.orig

The first AP configuration script (change your wifi country code with whatever you want):

ssid="MySSID"
psw="MyPSW"

sudo raspi-config nonint do_wifi_country IE
sudo DEBIAN_FRONTEND=noninteractive apt-get install -y netfilter-persistent iptables-persistent
sudo touch /etc/dhcpcd.conf.ap
sudo sed -i '$ainterface wlan0\nstatic ip_address=10.3.141.1/24\nnohook wpa_supplicant' /etc/dhcpcd.conf.ap
sudo touch /etc/sysctl.d/routed-ap.conf
echo "net.ipv4.ip_forward=1" | sudo tee /etc/sysctl.d/routed-ap.conf
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
sudo netfilter-persistent save
sudo touch /etc/dnsmasq.conf.ap
echo "interface=wlan0" | sudo tee /etc/dnsmasq.conf.ap
sudo sed -i '$adhcp-range=10.3.141.5,10.3.141.100,255.255.255.0,24\ndomain=ap\naddress=/rpi.ap/10.3.141.1' /etc/dnsmasq.conf.ap
sudo touch /etc/hostapd/hostapd.conf.ap
echo "country_code=IE" | sudo tee /etc/hostapd/hostapd.conf.ap
sudo sed -i -e '$a\' -e "interface=wlan0\nssid=${ssid}\nhw_mode=g\nchannel=2\nmacaddr_acl=0\nauth_algs=1\nignore_broadcast_ssid=0\nwpa=2\nwpa_passphrase=${psw}\nwpa_key_mgmt=WPA-PSK\nwpa_pairwise=TKIP\nrsn_pairwise=CCMP" /etc/hostapd/hostapd.conf.ap
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