SonicWALL 5.8.1 Manuale Utente

The following are circumstances in which Transparent Mode might be preferable over L2 Bridge 
Mode:

Two interfaces are the maximum allowed in an L2 Bridge Pair. If more than two interfaces 
are required to operate on the same subnet, Transparent Mode should be considered.

PortShield interface may not operate within an L2 Bridge Pair. If PortShield interfaces are 
required to operate on the same subnet, Transparent Mode should be considered.

VLAN subinterfaces, supported on SonicWALL NSA series appliances, may not operate 
within an L2 Bridge Pair. If VLAN subinterfaces are required to operate on the same subnet, 
Transparent Mode should be considered. It is, however, possible to configure a VLAN 
subinterface on an interface that is part of a Bridge-Pair; the subinterface will simply 
operate independently on the Bridge-Pair in every respect.

L2 Bridge Mode is more similar in function to the CSM than it is to Transparent Mode, but it 
differs from the current CSM behavior in that it handles VLANs and non-IPv4 traffic types, which 
the CSM does not. Future versions of the SonicOS CF Software for the CSM will likely adopt 
the more versatile traffic handling capabilities of L2 Bridge Mode.

Stateful Packet 
Inspection

Full stateful packet inspection will be 
applied to all IPv4 traffic traversing the L2 
Bridge for all subnets, including VLAN traffic 
on SonicWALL NSA series appliances.

Full stateful packet inspection will applied 
to traffic from/to the subnets defined by 
Transparent Mode Address Object 
assignment.

Security services

All security services (GAV, IPS, Anti-Spy, 
CFS) are fully supported. All regular IP 
traffic, as well as all 802.1Q encapsulated 
VLAN traffic.

All security services (GAV, IPS, Anti-Spy, 
CFS) are fully supported from/to the 
subnets defined by Transparent Mode 
Address Object assignment.

Broadcast traffic

Broadcast traffic is passed from the 
receiving Bridge-Pair interface to the 
Bridge-Partner interface.

Broadcast traffic is dropped and logged, 
with the possible exception of NetBIOS 
which can be handled by IP Helper.

Multicast traffic

Multicast traffic is inspected and passed 
across L2 Bridge-Pairs providing Multicast 
has been activated on the Firewall > 
Multicast page. It is not dependent upon 
IGMP messaging, nor is it necessary to 
enable multicast support on the individual 
interfaces.

Multicast traffic, with IGMP dependency, is 
inspected and passed by Transparent 
Mode providing Multicast has been 
activated on the Firewall > Multicast page, 
and multicast support has been enabled on 
the relevant interfaces.