Creating second physical LAN but no internet access is available

Hello Daniel,

Thank you for contacting the Sophos Community.

To what port you are connecting your Switch, and which IP address in the Sophos Firewall this port has?

If, for example, Port1 is the one where your switch is connected, if you configure Port 3 with the same subnet, you’ll have an overlap that will cause routing issues. 

So either you can assign a different subnet to port 3 (e.g 172.16.17.1) or you can bridge the Port1 and Port3 interfaces to be in the same subnet.

I would suggest you go with a different subnet. 

Regards, 

Hello Daniel,

Thank you for contacting the Sophos Community.

To what port you are connecting your Switch, and which IP address in the Sophos Firewall this port has?

If, for example, Port1 is the one where your switch is connected, if you configure Port 3 with the same subnet, you’ll have an overlap that will cause routing issues. 

So either you can assign a different subnet to port 3 (e.g 172.16.17.1) or you can bridge the Port1 and Port3 interfaces to be in the same subnet.

I would suggest you go with a different subnet. 

Regards, 

Attached is my network interfaces, my switch is plugged into port 1, port 2 is my WAN coming in from fiber to home, port 3 is my secondary LAN with my proxmox box directly connected to sophos firewall 

Hello,

So make sure the device connected to the Port3 has an IP in that subnet, and the DG is the 172.16.17.1 

Regards,

Hello,

I have done that - the physical device has an up 17.16.17.2 with the DG is this gateway ? As 17.16.17.1 . 

still no internet 

Hello Daniel,

Make sure the IP is 172.16.17.x not 17.16.17.x

Why? All devices that want to communicate outside their subnet need a Gateway to know where to send the traffic that doesn't match their subnet. In the Case the Sophos Firewall is the DG for this PC, and it has IP 172.16.17.1

Regards,