SonicOS 7 System

Technical Documentation > SonicOS 7 System > Interfaces > Interface Settings IPv4 > Layer 2 Bridged Mode

Layer 2 Bridged Mode

SonicOS includes L2 (Layer 2) Bridged Mode, a method of unobtrusively integrating a firewall into any Ethernet network. L2 Bridged Mode is ostensibly similar to SonicOS’s Transparent Mode in that it enables a firewall to share a common subnet across two interfaces, and to perform stateful and deep-packet inspection on all traversing IP traffic, but it is functionally more versatile.

In particular, L2 Bridged Mode employs a secure learning bridge architecture, enabling it to pass and inspect traffic types that cannot be handled by many other methods of transparent appliance integration. Using L2 Bridged Mode, a SonicWall firewall can be non-disruptively added to any Ethernet network to provide in-line deep-packet inspection for all traversing IPv4 TCP and UDP traffic. In this scenario, the appliance is not used for security enforcement, but instead for bidirectional scanning, blocking viruses and spyware, and stopping intrusion attempts.

Unlike other transparent solutions, L2 Bridged Mode can pass all traffic types, including IEEE 802.1Q VLANs, Spanning Tree Protocol, multicast, broadcast, and IPv6, ensuring that all network communications continues uninterrupted.

Another aspect of the versatility of L2 Bridged Mode is that you can use it to configure IPS Sniffer Mode. Supported on SonicWall firewalls, IPS Sniffer Mode uses a single interface of a Bridge-Pair to monitor network traffic from a mirrored port on a switch. IPS Sniffer Mode provides intrusion detection, but cannot block malicious traffic because the appliance is not connected inline with the traffic flow. See IPS Sniffer Mode for more information.

L2 Bridged Mode provides an ideal solution for networks that already have existing appliances, and do not have immediate plans to replace their existing appliances, but wish to add the security of SonicWall deep-packet inspection and security services, such as Intrusion Prevention, Gateway Anti-Virus, and Anti-Spyware. If you do not have SonicWall security service subscriptions, you can sign up for free trials atMySonicWall.

You can also use L2 Bridged Mode in a High Availability deployment. This scenario is explained in the Layer 2 Bridged Mode with High Availability.

Link Aggregation is not supported in Layer 2 Bridged Mode.

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