Connecting Android-Tablet to WiFi without Internet Access - Android Q&A, Help & Troubleshooting

Hello,
I have troubles to connect my android tablet to a subnet of my WiFi that has no connection to the internet:
the router is set to IP-address 192.168.178.1 (subnet mask is 255.255.255.0). The tablet and a few other devices (that shall have no connection to the internet) are set to fixed adresses within the range 192.168.182.xxx. As the router does not respond within this adress range, the devices may communicate with each other but do not have internet access.
This works well e.g. with a smartphone with Android v8.1.0.
The tablet (Android v7.1.2 (LineageOS 14.1)) however keeps disconnecting and reconnecting all the time and toggles between the states "not connected" and "connected, no internet".
I have read about the 'captive portal check' as a possible cause for this behaviour. Therefore, I disabled this check by executing the command "settings put global captive_portal_mode 0" in a terminal. The immediate result is that the WiFi now toggles between "not connected" and "connected", so that did have some effect. However it still keeps reconnecting.
Does anybody have an idea what functionality may cause these reconnects? How can I achieve the same behaviour as with the android smartphone that simply maintains a stable WiFi connection?
Thanks in advance!

Related

Error: No Internet Connection when NOT Connected to Internet

I've set up a private network wireless with a webserver for a project I'm working on. I do not (and cannot) have internet connectivity on this network. Whenever I bring up the web browser on the TP (3.04) it spams me with "Error: No Internet Connection" messages and I can't access the webserver. I do not believe I had this problem with spamming on 3.02.
Does anyone know how to disable this or at least know the mechanism that the TP uses to determine if it has Internet connectivity? Maybe I can spoof it.

All android devices - full wifi signal, no internet - other devices work fine

Hi there,
I have near been driven to madness by this problem so im admitting defeat and opening it up to all and everyone.
Very quick history - I have weak signal on the top floor of my house, so i purchased a TP LINK WR702N mini router. I have set this up as a wireless repeater on the top floor, and for the majority of my devices it works great. On my sisters windows laptop, my girlfriends iPhone and iPad, they all see the network, connect with full strength and receive 54Mbps. On all of these devices, I can enter 192.168.1.254 and reach the repeaters settings page, or enter 192.168.1.1 and reach my main router (downstairs) settings page. This suggests to me that everything works fine.
When i connect with an android device (either my Nexus 10 or my samsung galaxy S2) the moment they pick up the strong repeater signal - they lose internet connection. The are connected with 100% and 54Mbps speed to the repeater - but they cannot access the web. I can bring up 192.168.1.254 for the repeater, but they will not access 192.168.1.1 for the main router - I believe this is the problem.
I have tried changing the settings on my main router - I have changed the whole network from WPA to WEP encryption, to no avail
I have changed the android advanced wifi settings, changing to fixed IP on both of the android devices and setting the default gateway and DNS to be 192.168.1.1
I turned off my devices, reset the main router, then turned on the repeater - this appeared to fix the problem - but when i turned the repeater on last night I couldnt get internet access, so i retried this step and it didnt work
as a note, all of the devices on my network have a fixed IP set from my main router - these correspond to the fixed IPs on my android devices.
I have spoke to Google and TP Link supprt, each blame the other, and now I really dont know what to do.
Thanks
::bump::
Make sure your devices do not send out, nor honour, ICMP redirects. Since your are running both on the same subnet, there's a possibility your repeater sends out an ICMP redirect once your Android device addresses the main router, since it IP topological is a closer way talking directly.
Or, use different subnets.

[Q] How to ignore BT Wifi Access Points?

I have just bought a Q88 Tablet which for the money is proving to be excellent but I have a niggly problem with wifi dropouts which has highlighted another issue as described below.
I don't have BT Broadband but my Android tablet shows BT_Wifi and BT_Wifi_with_FON during scans presumably from a neighbours house. Unlike other wifi access points there appears to be no way to tell Android to FORGET or IGNORE these blessed things as no option is given to do so when you click on them within wifi settings and they can cause delays sometimes when my tablet is trying to reconnect to my home router.
Anyone know of a way to tell Android to ignore these BT pain in the a**s access point broadcasts?
The options in my Q88 Advanced Wifi screen are as follows :-
Network notification
Keep wi-fi on during sleep
Avoid poor connections - I've switched this on to try and filter out neighbours broadcasts
Wifi optimisation
I'm using the 'wifi fixer' app to try and help resolve my dropout issues but as yet it doesn't have a way of telling Android to ignore BT requests.

Ways for organize direct persistent TCP/IP connection to Android device via Internet?

I need persistent SSH access to my Android device from Internet. There are many apps that can listen ports on device external IP, but main problem is that most of Russian (and, I think, many other countries) cellular providers (GPRS, 3G, LTE, etc) close all ports from external access, even if device have white IP address. So via cellular network there are no way directly connect to device, and I can get direct access device only via WiFi neworks.
I want find any way for organize persistent access to my device via static address and port. The way where I don't need to check current wifi ip address of each network and type it for give access, but use something stable like myphone.somehost.com:12345.
Popular way for this is organize SSH Tunnel via external ssh server with white IP address. I have the server and already try this way (SSHDroid app as SSH server with bind to localhost:2222 port; SSH Autotunnel app for organize tunnel), but the problem is with too slow reconnecting after Android device change IP address (got reconnect on cellular network, or swith to/from WiFi) - problem with establishing new connection can continue about 10-30 minutes - this is too long.
So the Question: Is there any way to organize stable direct TCP/IP access to custom port on Android device, that work normally and reconnects quickly on unstable network with often reconnects and switch wifi/3g network.
Programs like Airdroid and Webkey provide direct access to device via http protocol, and works good via unstable connection. But I need to connect via SSH and other open protocols, not via some web interface.
Murz said:
I need persistent SSH access to my Android device from Internet. There are many apps that can listen ports on device external IP, but main problem is that most of Russian (and, I think, many other countries) cellular providers (GPRS, 3G, LTE, etc) close all ports from external access, even if device have white IP address. So via cellular network there are no way directly connect to device, and I can get direct access device only via WiFi neworks.
I want find any way for organize persistent access to my device via static address and port. The way where I don't need to check current wifi ip address of each network and type it for give access, but use something stable like myphone.somehost.com:12345.
Popular way for this is organize SSH Tunnel via external ssh server with white IP address. I have the server and already try this way (SSHDroid app as SSH server with bind to localhost:2222 port; SSH Autotunnel app for organize tunnel), but the problem is with too slow reconnecting after Android device change IP address (got reconnect on cellular network, or swith to/from WiFi) - problem with establishing new connection can continue about 10-30 minutes - this is too long.
So the Question: Is there any way to organize stable direct TCP/IP access to custom port on Android device, that work normally and reconnects quickly on unstable network with often reconnects and switch wifi/3g network.
Click to expand...
Click to collapse
I've managed this thing in the past with:
A continuously running server with a static IP address running SSHd with the option "GatewayPorts on". Let's say the server is at ssh.example.com.
You have to run an sshd daemon on your Android device.
You can then run the following script on your Android device:
Code:
#!/system/bin/sh
REMOTE_HOSTNAME=ssh.example.com
FORWARDED_PORT=2000
while :
do
ssh -R " $FORWARDED_PORT:127.0.0.1:22" "$REMOTE_HOSTNAME” "sleep 86400"
sleep 60
done
You'd have to change FORWARDED_PORT for every Android device and strange for authentication.
Once you have this set up you will be able to connect from anywhere by sshing to ssh to ssh.example.com port 2000.
Fif_ said:
Once you have this set up you will be able to connect from anywhere by sshing to ssh to ssh.example.com port 2000.
Click to expand...
Click to collapse
Fif_, thanks, I already try this way via SSHDroid and SSH Autotunnel, but after each disconnect (device change IP) I got lost connection abut 5-20 munites - new port forward cannot be established, because old session is still active and waiting timeout, and after 10-20 retries timeout is end and new ssh tunnel established normally.
If I decrease SSH timeouts to 5 seconds, I got very often disconnects and reconnects, that eats traffic and device battery. And after each disconnect I got dropped session on client side and need to connect again for continue working.
So SSH Tunnelling is bad way for non-stable and slow internet connection with dynamic IP address.
At now very popular is websocket protocol, that seems works well on bad connection and quickly restore session after disconnecting and changing IP (without aborting processes). But I can't understand how I can use it to proxy SSH session.
Murz said:
Fif_, thanks, I already try this way via SSHDroid and SSH Autotunnel, but after each disconnect (device change IP) I got lost connection abut 5-20 munites - new port forward cannot be established, because old session is still active and waiting timeout, and after 10-20 retries timeout is end and new ssh tunnel established normally.
Click to expand...
Click to collapse
You can mitigate that issue by checking that the reverse tunnel is up and running on the server.
If you create the following as checkssh:
Code:
#!/bin/bash
set -eu
while :
do
coproc nc localhost "$1" || exit 1
banner=''
read -t 30 banner <&${COPROC[0]} || exit 1
case "$banner" in
SSH-*) ;;
*) exit 1;;
esac
eval "exec ${COPROC[1]}>&-"
wait || :
sleep 30
done
Then change that line in the script I sent before:
Code:
ssh -R "$FORWARDED_PORT:127.0.0.1:22" "$REMOTE_HOSTNAME" "/path/to/checkssh $FORWARDED_PORT"
You should have much more luck keeping the connection up.
You may want to tweak timeouts to conserve battery.
Murz said:
If I decrease SSH timeouts to 5 seconds, I got very often disconnects and reconnects, that eats traffic and device battery. And after each disconnect I got dropped session on client side and need to connect again for continue working.
So SSH Tunnelling is bad way for non-stable and slow internet connection with dynamic IP address.
At now very popular is websocket protocol, that seems works well on bad connection and quickly restore session after disconnecting and changing IP (without aborting processes). But I can't understand how I can use it to proxy SSH session.
Click to expand...
Click to collapse
Have you thought about running an always-on VPN?
If say you run an always on VPN from your phone to a target machine, then with a little bit of iptables trickery you can achieve what you want.

Wifi connects then immediately disconnects

Hello
I'm having trouble connecting to a lot of Wifi networks that most other people with Android and Apple phones have no problems with, including my home network.
Here's what happens:
Turn on WIfi, select SSID, type in the correct password. It connects for about a second (I know because snapchats etc, pop-up), then disconnects and changes to "Saved".
Then the SSID disappears from the list of available networks, and exists only in the Saved Networks section. If tap it I get only "Forget" & "Cancel".
To try to work out what was going on I enabled Developer options and set "Enable Wi-Fo verbose logging".
If I go through the same cycle, it connects for a second, then goes to saved and shows this underneath the SSID
"NETWORK_SELECTION_DISABLED+ASSOCIATION REJECTION=1"
I'm on Android version 7.1.2 Build No. TOS137B - N2G47H
The phone isn't rooted or anything
Can you tell me what's going on and how to fix it?
Hi there
Just wondering if you have McAfee installed?
I'm not much of an expert but I had a similar issue with WiFi on my Medion X2050 (I think that's what it's called) and I uninstalled McAfee and the problem was gone.

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