McAfee Email and Web Security Appliance 5.5, Installation Manual

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traffic is intercepted and scanned, therefore the device is said to operate as a transparent
bridge.
Figure 3: Transparent bridge mode
Transparent router mode
In transparent router mode, the device scans email traffic between two networks. The device
has one IP address for outgoing scanned traffic, and must have one IP address for incoming
traffic.
The communicating network servers are unaware of the intervention of the device — the device’s
operation is
transparent to the devices.
What the device does
In transparent router mode, the device connects to your networks using the LAN1 and LAN2
ports. The device scans the traffic it receives on one network, and forwards it to the next
network device on a different network. The device acts as a router, routing the traffic between
networks, based on the information held in its routing tables.
Configuration
Using transparent router mode, you do not need to explicitly reconfigure your network devices
to send traffic to the device. You need only configure the routing table for the device, and
modify some routing information for the network devices on either side of it (the devices
connected to its LAN1 and LAN2 ports). For example, you might need to make the device your
default gateway.
Pre-installation
Considerations about Network Modes
McAfee Email and Web Security Appliance 5.5 Installation Guide 14