system apps connecting to internet. Can disable it?

[lg4xhd]

Hello.

I have version 4.8.22 of miui.
I have installed android firewall. Firewall detected and block system apps.
Why system apps connecting to the internet?

Example Firewall log:
---------
AppID : 10014
App name: SMS
Blocked packets: 8

---------
AppID : 10036
App name: File explorer
Blocked packets: 16

---------
AppID : 10066
App name: TrafficControl
Blocked packets: 12


---------
I dont have account in phone.

Best regards.

 

[lg4xhd]

Maybe is synchro or cloud services, maybe ads. I don't no.
It's possible option to disable it definitely?