How to direct Internet traffic via 4G modem while connected to a LAN with gateway?

[Bo Berglund]

On Thu, 23 Sep 2021 13:39:33 -0400, Peter Silva <peter at bsqt.homeip.net> wrote:

>investigate ip route add, ip route del.
>assuming windows box is on the same LAN as your pi's eth0, you should be
>able to just change the default route to use the 4G interface.
>
>I think you can just do this manually for now, on the assumption that the
>eth0 will be gone when it comes time to deploy and it will "just work."
>
>

I was advised on the RPi forum to do as follows:

sudo nano /etc/dhcpcd.conf

#add the following to the end of the file:
interface usb0
metric 100

Then
ifconfig usb0 down
ifconfig usb0 down

And after the connect time it was indeed working.
I could start a speedtest while connected via SSH on eth0 and the RPi sent the
command over 4G.


-- 
Bo Berglund
Developer in Sweden