I use an access point without internet to transfer files via TCP/IP socket between android devices to a windows pc. I use several models and OS of android (OS between 9-13)
Currently we work only with a local network. I need to add a 4G modem so the android clients will be able to access to the internet. In order to achieve that, i configured the AP & modem as following:
AP:
DHCP server: on
DHCP pool: 100-200
IP - 192.168.100.3
gateway - 192.168.100.2
Primary DNS: 8.8.8.8
Secondary DNS: 8.8.4.4
4G modem:
DHCP server - off
IP address: 192.168.100.2
Windows PC:
The network adapter is configured to static ip address - 192.168.100.1
With the configuration above, i have access to the internet from the android devices.
My problem is started when the gateway(modem) is not reachable. (In case which i want to work locally, without access to internet)
The android clients are disconnecting & connecting automatically from the network.
During the reconnecting process, i can see that the device is getting an ip address as configured in the DHCP server.
I assume that the device is trying to reach the gateway and when the gateway is not reachable the connection is lost automatically.
I tried to configure the android device with a static ip in the same way as the DHCP server and it works fine. the device is stay connected to the network.
When i back to dhcp, the device drop the connection every 1-2 seconds.
The problem occurs only in few models.
PDA UNITECH HT730 with OS 10.
PDA UNITECH EA510 with OS 9.
PDA ZEBRA (not sure which model) OS 10.
In my phone Samsung S22 ultra (OS 13) or Samsung A51 (OS 11) i can access to the network without any issues.
I tried to use the manufacturer support, but i saw it happens in several manufacturers so i started to think that it is an android issue.
Do you have any suggestions how to skip the DNS resolving issue?