LTE router: turn off broadband but keep SMS working

RouterOS General
1

I am using an LtAP-2HnD (ROS 7.23.1) while travelling Europe. Sometimes, when using a ferry, I need to turn off the broadband functionality as the internet at sea can be extremely expensive and completely drains my prepaid internet credits.

What I usually do is disable the lte1 interface while I'm still connected through wifi and, when on shore again, connect with wifi and enable the lte1 interface again.

What I would like to do is turn the broadband connection off and on using an SMS command, which is more convenient and which can be done remotely as well.

When I disable lte1, the router does not receive SMS anymore so that's no solution.

In some other topic it is suggested to remove the default APN, but I'm not sure if that will keep the SMS-receiving function up and running. And how to set up the default APN again.

Another suggestion was to set up a firewall rule to disable all traffic over lte1. Question for me is if this indeed would reduce the broadband traffic to 0, even if the broadband connection to the default APN is kept alive?

Also roaming can be turned off and on, but I'm not sure if that will keep up the SMS reception.

What would be the best way to disable broadband connection and consumption while the SMS functionality remains up and running.

2

I would attack the APN as suggested. As it cannot be disabled, I think the easiest fix, if good enough, is just to remove the default route:

 /interface/lte/apn/set [find ] add-default-route=no

It might not reduce the traffic to zero, but it will be very close as traffic to the Internet will not be routed over the LTE interface.

SMS traffic is not dependent on APNs, so deleting it and restoring it is definitely also an option.

3

What would be the procedure to restore the default APN?

Would it be an option to create a second APN profile with a fake APN-name and not delete the default APN but switch to the fake APN profile?

4

Ahhh... sorry @xrlls I did not read your message well. You suggested to just set the default-route ot 'NO'. Will try that anyway

5

Setting add-default-route=no is not going to work. I get the error:

Can't use DNS without a route.

6

True I get the same errror. I thought I tried it yesterday. This works for me:

/interface/lte/apn/set [find ] add-default-route=no use-peer-dns=no

And to enable:

/interface/lte/apn/set [find ] add-default-route=yes use-peer-dns=yes
7

OK, tried it, but it also disables incoming SMS...

8

Hmm... tried it on a SXT LTE and a wAP AC LTE6 kit, and works for me on both. SMS is received when default route and peer dns are both set to 'no'.

Anyway, good luck :slight_smile:

9

Not sure what I did wrong the first time but now running the commands I indeed could receive SMS messages after setting add-default-route=no use-peer-dns=no.

Some things to find out is how to minimize the attempt for data traffic. Certainly need to disable my wireguard setup and the test for internet connection.