A bridge interface can be helpful in specific situations. Let us give you one use case here!
Let´s imagine you have a firewall with SFP ports like an ATP800 or USG FLEX 700.
Maybe you would like to port group your SFP port with one of the copper ports so that you have the same subnet and firewall zone for both ports.
But you see this is not possible:
The SFP ports are greyed out...
So how can we work around this?
In this case, we want our SFP port number 13 and our port 11 both to be in the same local LAN subnet and firewall zone and provide DHCP to clients.
As we can not put them into a port group, at first we set the
- Interface type to "Internal"
- Firewall Zone "LAN"
- IP and subnet mask to 0.0.0.0
- disabling DHCP by setting it to none
This needs to be done for both interfaces (the copper and SFP port)!
Now we create the bridge interface under Configuration > Network > Bridge and adjust these settings:
- Interface Type "Internal"
- Zone "LAN"
- Adding the interfaces to be grouped (here P13 and P11)
- Configuring the IP settings of the interface as well as DHCP server
Now you have the same LAN subnet on the SFP and copper port, just as if you would have combined them via port grouping!
We might enhance this article later with more use cases for the bridge interface.