User's Guide

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Link: Advanced -> Ethernet Bridge
The Cayman Gateway can be used as a bridge, rather than a router. A
bridge is a device that joins two networks. As an Internet access device, a
bridge connects the home computer directly to the service provider’s net-
work equipment with no intervening routing functionality, such as Network
Address Translation. Your home computer becomes just another address
on the service provider’s network. In a DSL connection, the bridge serves
simply to convey the digital data information back and forth over your tele-
phone lines in a form that keeps it separate from your voice telephone sig-
nals.
If your service provider’s network is set up to provide your Internet connec-
tivity via bridge mode, you can set your Cayman Gateway to be compatible.
Bridges let you join two networks, so that they appear to be part of the
same physical network. As a bridge for protocols other than TCP/IP, your
Gateway keeps track of as many as 255 MAC (Media Access Control)
addresses, each of which uniquely identifies an individual host on a net-
work. Your Gateway uses this bridging table to identify which hosts are
accessible through which of its network interfaces. The bridging table con-
tains the MAC address of each packet it sees, along with the interface over
which it received the packet. Over time, the Gateway learns which hosts are
available through its WAN port and/or its LAN port.
When configured in Bridge Mode, the Cayman will act as a pass-through
device and allow the workstations on your LAN to have public addresses
directly on the internet.
☛ NOTE:
In this mode the Cayman is providing NO firewall protection as is
afforded by NAT. Also, only the workstations that have a public
address can access the internet. This can be useful when you
need to use all five of your static public IPs on the LAN.