Access Point stops working after a few seconds

[JangoJR]

Hello Guys,

recently I bought myself a Raspberry Pi 4 and after installing a Plex-Server I tried to use the Pi as a routed access point. To do so I followed this tutorial (https://www.raspberrypi.org/documentati ... -routed.md). For a few minutes it all works fine and I could connect devices to it, but after a few reboots it suddenly stopped working and I can't figure out why. All the devices disconnect from the network and they are unable to reconnect even though the WiFi is still visible. Sometime after a "hard reboot" (unplugging the Pi) the Devices reconnect to the Network for a minute but disconnect short after. Did anybody has the same Problem and solved it?

Thanks in advanced

[epoch1970]

Sounds like a power issue to me.
Which PSU do you use?

[JangoJR]

Thanks for the fast response,

I am using the office Raspberry Pi Power Supply from the Pi foundation. My Pi sits in an argon one case and haven't been overclocked. Also the Network worked for a good hour until I rebooted the Pi.

Best regards JangoJR

[thnroger]

I did have very similar issues on my Raspberry Pi 4 Model B Rev 1.4 after configuration from https://www.raspberrypi.org/documentati ... -routed.md
Looks like I've resolved it with update as below in /lib/systemd/system/hostapd.service

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After=network.target

replaced with

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After=dnsmasq.service

[JangoJR]

Thanks for the tip thnroger
I did as you said and rebooted with "sudo systemctl reboot" aferwards, but sadly nothing changed. I am still able to see the network on my phone but as before I am unable to connect. I think this might has to deal with the DHCP-Server hence my device don't seam to recive an IP-Address. Also the previously connected WiFi-Plugs aren't connecting itself to the Network aswell.

[thnroger]

Sorry to hear
You do have wlan0 as below?

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pi@PI4:~ $ ifconfig wlan0
wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.4.1  netmask 255.255.255.0  broadcast 192.168.4.255

[JangoJR]

The section for wlan0 within ifconfig looks like this:

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wlan0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.4.1  netmask 255.255.255.0  broadcast 192.168.4.255
        inet6 fe80::9ab6:6aa:cfe5:3136  prefixlen 64  scopeid 0x20<link>
        ether dc:a6:32:b7:fb:96  txqueuelen 1000  (Ethernet)
        RX packets 778  bytes 115295 (112.5 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 450  bytes 51073 (49.8 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

It seams a bit longer than your entry, but I can't find anything suspicious.

[thnroger]

I did skip some lines from my ifconfig wlan0 command
When I had the issue I could not see my WLAN when using hw_mode=g (2.4GHz) but hw_mode=a (5GHz) was visible and working OK

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pi@PI4:~ $ sdiff -s /etc/hostapd/hostapd.conf /etc/hostapd/hostapd.conf_5
hw_mode=g                                                     | hw_mode=a
channel=6                                                     | channel=48

You could also check if sudo systemctl status dnsmasq.service and/or sudo systemctl status hostapd.service has "anything to say"

[JangoJR]

I am currently physicaly unable to access my Pi because I lend it to a friend hwo wants to test a project with it. Once I have it back, I will test your idear to change the mode.

[thnroger]

OK
It might also be useful to try

grep dnsmasq /var/log/syslog

while trying to connect
Should give something like below if OK

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Aug  6 02:24:55 PI4 dnsmasq-dhcp[551]: DHCPREQUEST(wlan0) 192.168.4.13 58:c5:cb:88:75:81
Aug  6 02:24:55 PI4 dnsmasq-dhcp[551]: DHCPACK(wlan0) 192.168.4.13 58:c5:cb:88:75:81 Galaxy-A5-2017
Aug  6 13:56:08 PI4 dnsmasq-dhcp[551]: DHCPREQUEST(wlan0) 192.168.4.13 58:c5:cb:88:75:81
Aug  6 13:56:08 PI4 dnsmasq-dhcp[551]: DHCPACK(wlan0) 192.168.4.13 58:c5:cb:88:75:81 Galaxy-A5-2017