I have managed to turn my Raspberry Pi into an access point following these instructions: https://raspberrypi.stackexchange.com/questions/95072/access-point-as-wifi-router-repeater-with-additional-wifi-dongle/95073#95073 However, everything connects to the access point except my android devices (A Samsung Galaxy Note 8 and a Samsung Galaxy S5). A similar problem is presented in this question: https://raspberrypi.stackexchange.com/questions/93660/android-cannot-connect-to-pis-wlan However, the answer given there does not apply to me since I have the file `/etc/systemd/network/08-wlan0.network` exactly as in the first link. (hence with DHCP server activated): [Match] Name=wlan0 [Network] Address=192.168.4.1/24 IPForward=yes DHCPServer=yes [DHCPServer] DNS=84.200.69.80 1.1.1.1 How can I fix it? #Further information: ## Problem Description Both my devices can see the network. The Galaxy Note 8 keeps trying to connect, when I insert the password it says "Connecting..." under the SSID for approximately 3 seconds stops showing the message for 2 seconds and then keeps trying to connect. Almost the same with the Galaxy S5 with the difference that it also writes "Obtaining IP address" before stopping and then keeps retrying. ## Check on DHCP (as apparently is a known issue, see second link) Journalctl does not seem to show DHCP requests, hence I have extended the log as described here: https://superuser.com/questions/1187633/how-to-debug-systemd-networkd Launching `journalctl -b -u systemd-networkd`, I have tried to reconnect several times with my android devices From 12:16 on, however I see only two DHCP server requests. Jan 11 12:14:28 raspberrypi systemd-networkd[855]: Sent message type=signal sender=n/a destination=n/a path=/org/freedesktop/network1/link/_33 interface=org.freedesktop.DBus.Properties member=PropertiesCh Jan 11 12:16:04 raspberrypi systemd-networkd[855]: DHCP SERVER: REQUEST (rebinding/renewing) (0x4f98fb1a) Jan 11 12:16:04 raspberrypi systemd-networkd[855]: DHCP SERVER: ACK (0x4f98fb1a) Jan 11 12:17:39 raspberrypi systemd-networkd[855]: DHCP SERVER: REQUEST (rebinding/renewing) (0x26d7c444) Jan 11 12:17:39 raspberrypi systemd-networkd[855]: DHCP SERVER: ACK (0x26d7c444) ##Check on [email protected] I get root@raspberrypi:~ # journalctl -b -u [email protected] -- Logs begin at Sat 2020-01-11 10:03:13 CST, end at Sat 2020-01-11 12:28:44 CST. -- Jan 11 10:03:16 raspberrypi systemd[1]: Started WPA supplicant daemon (interface-specific version). Jan 11 10:03:17 raspberrypi wpa_supplicant[352]: Successfully initialized wpa_supplicant Jan 11 10:03:17 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-REGDOM-CHANGE init=USER type=COUNTRY alpha2=US Jan 11 10:03:21 raspberrypi wpa_supplicant[352]: wlan0: Could not connect to kernel driver Jan 11 10:03:21 raspberrypi wpa_supplicant[352]: Using interface wlan0 with hwaddr **DeviceMac** and ssid "**Device_SSID**" Jan 11 10:03:21 raspberrypi wpa_supplicant[352]: wlan0: interface state UNINITIALIZED->ENABLED Jan 11 10:03:21 raspberrypi wpa_supplicant[352]: wlan0: AP-ENABLED Jan 11 10:03:21 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-CONNECTED - Connection to **DeviceMac** completed [id=0 id_str=] Jan 11 10:04:47 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 10:04:47 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-CONNECTED **MAC_OF_PC1** Jan 11 10:05:12 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 10:05:12 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-CONNECTED **MAC_OF_PC2** Jan 11 10:05:19 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-REGDOM-CHANGE init=CORE type=WORLD Jan 11 10:05:19 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-REGDOM-CHANGE init=USER type=COUNTRY alpha2=US Jan 11 10:06:06 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 10:06:14 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 10:06:21 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 11:04:32 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-REGDOM-CHANGE init=CORE type=WORLD Jan 11 11:04:33 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-REGDOM-CHANGE init=USER type=COUNTRY alpha2=US Jan 11 11:13:47 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 11:13:55 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:16:25 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:16:32 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:16:32 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:16:48 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:16:55 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:17:03 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:17:15 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:17 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:25 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:33 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:41 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:49 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:18:57 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:19:05 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:19:13 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:20:15 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:20:23 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:20:31 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:28:22 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:28:29 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:28:37 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 11 12:28:44 raspberrypi wpa_supplicant[352]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 At least I see the connection attempts at their right times as `CTRL-EVENT-SUBNET-STATUS-UPDATE status=0`. I have also tried to submit a wrong password, in this case I get: Jan 11 12:37:12 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-POSSIBLE-PSK-MISMATCH **PhoneAddress** Jan 11 12:37:13 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-POSSIBLE-PSK-MISMATCH **PhoneAddress** Jan 11 12:37:14 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-POSSIBLE-PSK-MISMATCH **PhoneAddress** Jan 11 12:37:15 raspberrypi wpa_supplicant[352]: wlan0: AP-STA-POSSIBLE-PSK-MISMATCH **PhoneAddress** ## Ipv6? I found out that in order to download updates faster it was convenient to switch off RasPi Ipv6. Could this interfere? I had this doubt since when I connected to the network from a windows machine I found out in the WiFi properties that there is a Link-local IPv6 address. Since it is often claimed that Link-local is what is not supported in android, it might be that the Ipv6 settings are necessary for android to connect to a wifi network. But how to switch on IPv6 and set DHCP inside systemd-networkd? However from this: https://stackoverflow.com/questions/37978595/what-triggers-assigning-ipv6-link-local-address-in-android I deduce that android devices are capable of getting a link-local Ipv6 address. ## Another similar question https://raspberrypi.stackexchange.com/questions/90008/access-point-not-working-for-android-phones But the answers do not make sense to me. I have tried to change `/etc/systemd/network/08-wlan0.network` to [Match] Name=wlan0 [Network] Address=10.10.11.1/24 IPForward=yes DHCPServer=yes [DHCPServer] DNS=84.200.69.80 1.1.1.1 then from `ifconfig` on my laptop I get: wlo1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST> mtu 1500 inet 10.10.11.72 netmask 255.255.255.0 broadcast 10.10.11.255 inet6 fe80::aeee:ee4:1a78:6517 prefixlen 64 scopeid 0x20<link> ether **MACADDRESS** txqueuelen 1000 (Ethernet) RX packets 15397 bytes 8998330 (8.9 MB) RX errors 0 dropped 0 overruns 0 frame 0 TX packets 9034 bytes 2177688 (2.1 MB) TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0 And still can not connect from mobile. I also changed it to `Address=192.168.0.0/24` and I couldn't connect this time also from the pcs, however from `journalctl -b -u [email protected]` I got a different error from the pcs and the from the android devices (and the error given to the android devices is the same old one). Jan 12 09:33:43 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:33:47 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:33:51 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:34:07 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:34:11 raspberrypi wpa_supplicant[359]: wlan0: AP-STA-DISCONNECTED f8:54:b8:85:45:01 Jan 12 09:34:16 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:34:25 raspberrypi wpa_supplicant[359]: wlan0: AP-STA-DISCONNECTED 60:14:b3:6d:a0:af Jan 12 09:34:26 raspberrypi wpa_supplicant[359]: wlan0: CTRL-EVENT-SUBNET-STATUS-UPDATE status=0 Jan 12 09:34:26 raspberrypi wpa_supplicant[359]: wlan0: AP-STA-CONNECTED 60:14:b3:6d:a0:af Jan 12 09:35:11 raspberrypi wpa_supplicant[359]: wlan0: AP-STA-DISCONNECTED 60:14:b3:6d:a0:af ## Debugging from Android Thanks to `adb shell` I was able to launch `dumpsys wifi` on my galaxy S5, and I got Working connection ``` 01-12 14:16:22.185 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=33 state=6 BSSID=00:00:00:00:00:00 SSID=**PhoneNetwork**] 01-12 14:16:22.185 - Event [IFNAME=wlan0 Associated with **PhoneHotspotMAC**] 01-12 14:16:22.211 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=33 state=7 BSSID=**PhoneHotspotMAC** SSID=**PhoneNetwork**] 01-12 14:16:22.211 - Event [IFNAME=wlan0 WPA: RX message 1 of 4-Way Handshake from 6E.3F.F0 (ver=2)] 01-12 14:16:22.212 - Event [IFNAME=wlan0 WPA: Sending EAPOL-Key 2/4] 01-12 14:16:22.231 - Event [IFNAME=wlan0 WPA: RX message 3 of 4-Way Handshake from 6E.3F.F0 (ver=2)] 01-12 14:16:22.233 - Event [IFNAME=wlan0 WPA: Sending EAPOL-Key 4/4] 01-12 14:16:22.234 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=33 state=8 BSSID=**PhoneHotspotMAC** SSID=**PhoneNetwork**] 01-12 14:16:22.235 - Event [IFNAME=wlan0 WPA: Key negotiation completed with **PhoneHotspotMAC** [PTK=CCMP GTK=CCMP]] 01-12 14:16:22.235 - Event [IFNAME=wlan0 CTRL-EVENT-CONNECTED - Connection to **PhoneHotspotMAC** completed [id=33 id_str=]] 01-12 14:16:22.236 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=33 state=9 BSSID=**PhoneHotspotMAC** SSID=**PhoneNetwork**] 01-12 14:16:22.242 - wlan0: 4486:IFNAME=wlan0 GET FREQUENCY -> 2457 01-12 14:16:22.242 - wlan0: 4487:IFNAME=wlan0 SET_NETWORK 33 verified_password 1 -> true 01-12 14:16:22.251 - wlan0: 4488:IFNAME=wlan0 SAVE_CONFIG -> true 01-12 14:16:22.255 - wlan0: 4489:IFNAME=wlan0 SET pno 0 -> true 01-12 14:16:22.277 - wlan0: 4490:IFNAME=wlan0 PKTCNT_POLL -> TXGOOD=26571 TXBAD=508 RXGOOD=753 01-12 14:16:22.360 - wlan0: 4491:IFNAME=wlan0 DRIVER BTCOEXMODE 1 -> true 01-12 14:16:22.365 - wlan0: 4492:IFNAME=wlan0 DRIVER SETSUSPENDMODE 0 -> true 01-12 14:16:22.366 - wlan0: 4493:IFNAME=wlan0 SET ps 0 -> true 01-12 14:16:22.383 - wlan0: 4494:IFNAME=wlan0 LIST_NETWORKS -> network id / ssid / bssid / flags ``` Not working connection ``` 01-12 14:16:59.083 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=32 state=6 BSSID=00:00:00:00:00:00 SSID=**RasPiNetwork**] 01-12 14:16:59.084 - Event [IFNAME=wlan0 Associated with **RasPiMAC**] 01-12 14:16:59.084 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=32 state=7 BSSID=**RasPiMAC** SSID=**RasPiNetwork**] 01-12 14:16:59.085 - Event [IFNAME=wlan0 WPA: RX message 1 of 4-Way Handshake from DC.FF.96 (ver=2)] 01-12 14:16:59.086 - Event [IFNAME=wlan0 WPA: Sending EAPOL-Key 2/4] 01-12 14:16:59.093 - Event [IFNAME=wlan0 WPA: RX message 3 of 4-Way Handshake from DC.FF.96 (ver=2)] 01-12 14:16:59.095 - Event [IFNAME=wlan0 WPA: Sending EAPOL-Key 4/4] 01-12 14:16:59.095 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=32 state=8 BSSID=**RasPiMAC** SSID=**RasPiNetwork**] 01-12 14:17:03.112 - Event [IFNAME=wlan0 CTRL-EVENT-BIGDATA-DISCONNECT 2 36 1 2 dc:a6:32 2462 20 -40 72 2 0 x x 0 -92 0 0] 01-12 14:17:03.112 - Event [IFNAME=wlan0 CTRL-EVENT-DISCONNECTED bssid=**RasPiMAC** reason=2] 01-12 14:17:03.113 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=32 state=0 BSSID=**RasPiMAC** SSID=**RasPiNetwork**] 01-12 14:17:03.212 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=-1 state=3 BSSID=00:00:00:00:00:00 SSID=] 01-12 14:17:03.219 - Event [IFNAME=wlan0 CTRL-EVENT-SCAN-STARTED ] 01-12 14:17:05.402 - wlan0: 4581:IFNAME=wlan0 SET pno 0 -> true 01-12 14:17:05.404 - wlan0: 4582:IFNAME=wlan0 SCAN -> false 01-12 14:17:06.984 - wlan0: 4583:IFNAME=wlan0 SET pno 0 -> true 01-12 14:17:06.985 - wlan0: 4584:IFNAME=wlan0 SCAN -> false 01-12 14:17:07.024 - Event [IFNAME=wlan0 CTRL-EVENT-SCAN-RESULTS ] 01-12 14:17:07.024 - Event [IFNAME=wlan0 WPS-AP-AVAILABLE ] 01-12 14:17:07.043 - Event [IFNAME=wlan0 Trying to associate with **RasPiMAC** (SSID='**RasPiNetwork**' freq=2462 MHz level=-38) ] 01-12 14:17:07.046 - Event [IFNAME=wlan0 CTRL-EVENT-STATE-CHANGE id=32 state=5 BSSID=00:00:00:00:00:00 SSID=**RasPiNetwork**] 01-12 14:17:07.077 - wlan0: 4585:IFNAME=wlan0 LIST_NETWORKS -> network id / ssid / bssid / flags ``` Apparently `(reason = 2)` (https://www.cisco.com/assets/sol/sb/WAP371_Emulators/WAP371_Emulator_v1-0-1-5/help/Apx_ReasonCodes2.html) stands for "Previous authentication no longer valid". # Possible Path to a solution From here https://community.ui.com/questions/Android-devices-always-disconnecting-on-AP-AC-Pro/8512e697-1720-43b0-b0ee-591686b7f458?page=1 I got that "So somehow, having Multicast / Broadcast on my network kicks my Android devices". I don't even know how to chekc if my hotspot has those or can avoid those. Here this multicast issue is vaguely addressed: https://stackoverflow.com/questions/13221736/android-device-not-receiving-multicast-package In partucular the comment "This page has a wealth of information about which IP to use as per your needs. " reminds me of a similar comment in an answer at the link under the section "another similar question" however the link does not seem to help. Launching `systemd-resolve --status` I get ``` Link 4 (wlan0) Current Scopes: none DefaultRoute setting: no LLMNR setting: no MulticastDNS setting: no DNSOverTLS setting: no DNSSEC setting: allow-downgrade DNSSEC supported: yes ``` However I still can not connect from my smartphones.