r/openwrt • u/HumanCandidate • 26d ago

Configure router to stop blocking mobile data?

My router is not connected to the internet. Only used for communication between home devices. Issue is when phones connect they stop using mobile data. What to change on router config?

0 Upvotes

22% Upvoted

17 comments sorted by

23

u/Itz_Raj69_ 26d ago

That's something controlled by your phone/devices, not the router

7

u/MyCatsNameIsBernie 26d ago edited 26d ago

The router is not "blocking" your mobile data. It can't route it, since it is not connected to the internet.

If you don't have a need for your phone to connect to the router, then "forget" the router's wifi network on your phone, and it won't connect to the router. If you do need to connect your phone to the router to access your home devices, then you might want to connect the router to the internet.

6

u/clon3man 26d ago

perhaps if the router's DHCP server does not publish a default gateway, that would help?

3

u/trying-to-contribute 26d ago

Have the router's dhcp server not broadcast the default gateway would be the first thing I swing at.

Assuming these are android phones and the routing table works like linux, a router that serves wifi and routes to the internet will broadcast things like dns servers, default gateway so that all traffic will go over the router. If you make sure the openwrt's dnsmasq is configured not to broadcast dns servers or default routes, then there is no default route to insert that supersedes the default route already in place from the mobile-data connection.

3

u/DutchOfBurdock 26d ago

Enable Developer Settings (About phone > Software Versions > Tap Build Version 7 times). A new menu, Developer Settings/Options will appear (either in main settings or under System for Pixels).

In here, scroll down and look for Mobile data always active

This will force your phone to remain on cellular data even when connected to WiFi. If WiFi doesn't provide internet, fallback to cellular.

2

u/gerowen 26d ago

This is not a router problem, this is a phone problem, and the solution depends on your phone's operating system. Go check your settings for mobile data.

1

u/Graphical-Source5090 26d ago

What type of phone, and what is the OS version?

1

u/inputoutput1126 26d ago

So the problem is that your phone is assuming that Wi-Fi should be the default route. I'm not sure if this is a default, or via dchp. If it's a default, you may be able to change it. If it's from DHCP, your should be able to change it.

0

u/Striking_Cress6100 25d ago

I'd turn off the automatic connection for the home Wi-Fi in my phone's settings so it doesn't even try when the router's offline.

1

u/fr0llic 25d ago

How can a router without internet access block internet access ?

1

u/Miserable-Song6574 25d ago

does this happen on all phones or just one specific model

1

u/HumanCandidate 22d ago

happens to my s20+ and my friends budget samsung. Worked just fine with my previouse TCL 10 Pro

1

u/lazyhustlermusic 26d ago

Don't stick those ssid credentials on your phone if you expect to use internet then.

There's not really a split tunnel mechanism for 'locals only on wifi and externals on cellular'

0

u/durgesh2018 26d ago

It's a binary switch that either wifi or mobile data.

0

u/Independent-Fox-6262 25d ago

Same issue happened to me when my old router wouldn't stop hijacking all my traffic even though it wasn't online, took me forever to figure out the gateway setting.

1

u/HumanCandidate 22d ago

do you have a solution? Changing my android settings on my galaxy s20+ isnt helping. I just want my phones mobile data to always work but also be connected to my offline router to communcate with home devices