How to set up your FortiWeb : Configuring the network settings : Network interface or bridge?
 
Network interface or bridge?
To connect to the CLI and web UI, you must assign at least one FortiWeb network interface (usually port1) with an IP address and netmask so that it can receive your connections. Depending on your network, you usually must configure others so that FortiWeb can connect to the Internet and to the web servers it protects.
How should you configure the other network interfaces? Should you add more? Should each have an IP address? That varies. In some cases, you may not want to assign IP addresses to the other network interfaces.
Initially, each physical network port (or, on FortiWeb-VM, a vNIC) has only one network interface that directly corresponds to it — that is, a “physical network interface.” Multiple network interfaces (“subinterfaces” or “virtual interfaces”) can be associated with a single physical port, and vice versa (“redundant interfaces”/”NIC teaming”/”NIC bonding” or “aggregated links”). These can provide features such as link failure resilience or multi-network links.
 
FortiWeb does not currently support IPSec VPN virtual interfaces nor redundant links. If you require these features, implement them separately on your FortiGate, VPN appliance, or firewall.
Usually, each network interface has at least one IP address and netmask. However, this is not true for bridges.
Bridges (V-zones) allow packets to travel between the FortiWeb appliance’s physical network ports over a physical layer link, without an IP layer connection with those ports.
Use bridges when:
the FortiWeb appliance operates in true transparent proxy or transparent inspection mode, and
you want to deploy FortiWeb between incoming connections and the web server it is protecting, without changing your IP address scheme or performing routing or network address translation (NAT)
For bridges, do not assign IP addresses to the ports that you will connect to either the web server or to the overall network. Instead, group the two physical network ports by adding their associated network interfaces to a bridge.
Configure each network interface that will connect to your network or computer (see “Configuring the network interfaces” or “Configuring a bridge (V-zone)”). If you want multiple networks to use the same wire while minimizing the scope of broadcasts, configure VLANs (see “Adding VLAN subinterfaces”).
See also
Configuring the network interfaces
Adding VLAN subinterfaces
Link aggregation
Configuring a bridge (V-zone)