About the Transparent Router Mode
The Transparent Bridge mode is one of the transparent network modes you can configure for the proxy functions of a Secure Web Gateway appliance if you do not want to use an explicit (direct) mode.
In this mode, the clients are unaware of the appliance and need not be configured to direct their web traffic to it. The appliance is placed as a router immediately behind a firewall. A switch can be used for connecting the appliance to its clients. A routing table is used to direct the traffic.
For the high-level steps that are needed to configure this mode, see Configure the Transparent Router Mode.
Director and Scanning Nodes
If you are running several appliances as nodes within a cluster with Central Management administration, one node is usually configured as director, while the other nodes are configured as scanning nodes.
The director node receives web traffic from the clients and distributes it to the scanning nodes, which perform filtering activities on the traffic according to the rules that are implemented. Further handling of the traffic by the director or scanning nodes differs depending on what is configured. The director node can also perform filtering activities.
If you are only running one Secure Web Gateway appliance in your network and want to configure it in Transparent Router mode, you must still configure the director role for it to let it receive, filter, and forward web traffic.
We recommend that you configure at least two appliances as director nodes to avoid problems in case one of them goes offline.