SonicOS 7 System

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Technical Documentation > SonicOS 7 System > Interfaces > Interface Settings IPv4 > Layer 2 Bridged Mode > Configuring Layer 2 Bridged Mode > VLAN Integration with Layer 2 Bridged Mode

VLAN Integration with Layer 2 Bridged Mode

VLANs are supported on SonicWall Security Appliances. When a packet with a VLAN tag arrives on a physical interface, the VLAN ID is evaluated to determine if it is supported. The VLAN tag is stripped, and packet processing continues as it would for any other traffic. A simplified view of the inbound and outbound packet path includes these potentially reiterative steps:

  • IP validation and reassembly
  • Decapsulation (802.1q, PPP)
  • Decryption
  • Connection cache lookup and management
  • Route policy lookup
  • NAT Policy lookup
  • Access Rule (policy) lookup
  • Bandwidth management
  • NAT translation
  • Advanced Packet Handling (as applicable)
    • TCP validation
    • Management traffic handling
    • Content Filtering
    • Transformations and flow analysis (on SonicWall Security Appliances): H.323, SIP, RTSP, ILS/LDAP, FTP, Oracle, NetBIOS, Real Audio, TFTP
    • IPS and GAV

At this point, if the packet has been validated as acceptable traffic, it is forwarded to its destination. The packet egress path includes:

  • Encryption
  • Encapsulation
  • IP fragmentation

On egress, if the route policy lookup determines that the gateway interface is a VLAN subinterface, the packet is tagged (encapsulated) with the appropriate VLAN ID header. The creation of VLAN subinterfaces automatically updates the firewall’s routing policy table:

The auto-creation of NAT policies, Access Rules with regard to VLAN subinterfaces behave exactly the same as with physical interfaces. Customization of the rules and policies that govern the traffic between VLANs can be performed with customary SonicOS ease and efficiency.

When creating a zone (either as part of general administration, or as a step in creating a subinterface), a checkbox is presented on the zone creation page to control the auto-creation of a GroupVPN for that zone. By default, only newly created Wireless type zones have Create GroupVPN for this zone enabled, although the option can be enabled for other zone types by selecting the checkbox during creation.

Management of security services between VLAN subinterfaces is accomplished at the zone level. All security services are configurable and applicable to zones comprising physical interfaces, VLAN subinterfaces, or combinations of physical and VLAN subinterfaces.

Gateway Anti-Virus and Intrusion Prevention between the different workgroups can easily be employed with the use of VLAN segmentation, obviating the need for dedicated physical interfaces for each protected segment.

VLAN support enables organizations to offer meaningful internal security (as opposed to simple packet filtering) between various workgroups, and between workgroups and server farms without having to use dedicated physical interfaces on the firewall.

Here the ability to assign VLAN subinterfaces to the WAN zone, and to use the WAN client mode (only Static addressing is supported on VLAN subinterfaces assigned to the WAN zone) is illustrated, along with the ability to support WAN Load Balancing and failover. Also demonstrated is the distribution of SonicPoints throughout the network by means of connecting them to access mode VLAN ports on workgroup switches. These switches are then backhauled to the core switch, which then connects all the VLANs to the appliance through a trunk link.

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