to display the Edit Interface window, which allows you to configure the settings for the specified interface.
Chapter 13: Configuring Interfaces
Network > Interfaces
The Network > Interfaces page includes interface objects that are directly linked to physical interfaces. The SonicOS scheme of interface addressing works in conjunction with network zones and address objects. The interfaces displayed on the Network > Interfaces page depend on the type of SonicWALL appliance. The page pictured below is for SonicWALL TZ 100 or 200 Wireless-N appliances.
This chapter contains the following sections:
Setup Wizard
The Setup Wizard button accesses the Setup Wizard. The Setup Wizard walks you through the configuration of the SonicWALL security appliance for Internet connectivity. For Setup Wizard instructions, see Wizards > Setup Wizard.
Interface Settings
The Interface Settings table lists the following information for each interface:
Note: The X0 and X1 gigabit interfaces are for LAN and WAN, respectively. On the TZ 210 Series, X0 and X1 are the only gigabit interfaces. X2 is the only gigabit interface for the NSA 240.
Interface Traffic Statistics
The Interface Traffic Statistics table lists received and transmitted information for all configured interfaces.
The following information is displayed for all SonicWALL security appliance interfaces:
To clear the current statistics, click the Clear Statistics button at the top right of the Network > Interfaces page.
Physical and Virtual Interfaces
Interfaces in SonicOS can be:
Physical Interfaces
Physical interfaces must be assigned to a zone to allow for configuration of Access Rules to govern inbound and outbound traffic. Security zones are bound to each physical interface where it acts as a conduit for inbound and outbound traffic. If there is no interface, traffic cannot access the zone or exit the zone.
For more information on zones, see Network > Zones.
SonicOS Secure Objects
The SonicOS scheme of interface addressing works in conjunction with network zones and address objects. This structure is based on secure objects, which are utilized by rules and policies within SonicOS.
Secured objects include interface objects that are directly linked to physical interfaces and managed in the Network > Interfaces page. Address objects are defined in the Network > Address Objects page. Service and Scheduling objects are defined in the Firewall section of the SonicWALL security appliance Management Interface, and User objects are defined in the Users section of the SonicWALL security appliance Management Interface.
Zones are the hierarchical apex of SonicOS’s secure objects architecture. SonicOS includes predefined zones as well as allow you to define your own zones. Predefined zones include LAN, DMZ, WAN, WLAN, and Custom. Zones can include multiple interfaces, however, the WAN zone is restricted to a total of two interfaces. Within the WAN zone, either one or both WAN interfaces can be actively passing traffic depending on the WAN Failover and Load Balancing configuration on the Network > WAN Failover & LB page.
For more information on WAN Failover and Load Balancing on the SonicWALL security appliance, see Network > Failover & Load Balancing.
At the zone configuration level, the Allow Interface Trust setting for zones automates the processes involved in creating a permissive intra-zone Access Rule. It creates a comprehensive Address Object for the entire zone and a inclusively permissive Access Rule from zone address to zone addresses.
Transparent Mode
Transparent Mode in SonicOS uses interfaces as the top level of the management hierarchy. Transparent Mode supports unique addressing and interface routing.
Layer 2 Bridge Mode
SonicOS firmware versions 4.0 and higher includes L2 (Layer 2) Bridge Mode, a new method of unobtrusively integrating a SonicWALL security appliance into any Ethernet network. L2 Bridge Mode is ostensibly similar to SonicOS’s Transparent Mode in that it enables a SonicWALL security appliance 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 Bridge 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 security appliance integration. Using L2 Bridge Mode, a SonicWALL security appliance 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 SonicWALL UTM 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 Bridge Mode can pass all traffic types, including Spanning Tree Protocol, multicast, broadcast, and IPv6, ensuring that all network communications will continue uninterrupted.
L2 Bridge Mode provides an ideal solution for networks that already have an existing firewall, and do not have immediate plans to replace their existing firewall but wish to add the security of SonicWALL Unified Threat Management (UTM) deep-packet inspection, such as Intrusion Prevention Services, Gateway Anti Virus, and Gateway Anti Spyware. If you do not have SonicWALL UTM security services subscriptions, you may sign up for free trials from the Security Service > Summary page of your SonicWALL.
You can also use L2 Bridge Mode in a High Availability deployment. Layer 2 Bridge Mode with High Availability section
See the following sections:
Key Features of SonicOS Layer 2 Bridge Mode
The following table outlines the benefits of each key feature of layer 2 bridge mode:
L2 Bridging with Deep Packet Inspection
This method of transparent operation means that a SonicWALL security appliance can be added to any network without the need for readdressing or reconfiguration, enabling the addition of deep-packet inspection security services with no disruption to existing network designs. Developed with connectivity in mind as much as security, L2 Bridge Mode can pass all Ethernet frame types, ensuring seamless integration.
Secure Learning Bridge Architecture
True L2 behavior means that all allowed traffic flows natively through the L2 Bridge. Whereas other methods of transparent operation rely on ARP and route manipulation to achieve transparency, which frequently proves problematic, L2 Bridge Mode dynamically learns the topology of the network to determine optimal traffic paths.
Universal Ethernet Frame-Type Support
All Ethernet traffic can be passed across an L2 Bridge, meaning that all network communications will continue uninterrupted. While many other methods of transparent operation will only support IPv4 traffic, L2 Bridge Mode will inspect all IPv4 traffic, and will pass (or block, if desired) all other traffic, including LLC, all Ethertypes, and even proprietary frame formats.
Mixed-Mode Operation
L2 Bridge Mode can concurrently provide L2 Bridging and conventional security appliance services, such as routing, NAT, VPN, and wireless operations. This means it can be used as an L2 Bridge for one segment of the network, while providing a complete set of security services to the remainder of the network. This also allows for the introduction of the SonicWALL security appliance as a pure L2 bridge, with a smooth migration path to full security services operation.
Wireless Layer 2 Bridging
Use a single IP subnet across multiple zone types, including LAN, WLAN, DMZ, or custom zones. This feature allows wireless and wired clients to seamlessly share the same network resources, including DHCP addresses.The Layer 2 protocol can run between paired interfaces, allowing multiple traffic types to traverse the bridge, including broadcast and non-ip packets.
Key Concepts to Configuring L2 Bridge Mode and Transparent Mode
The following terms will be used when referring to the operation and configuration of L2 Bridge Mode:
Comparing L2 Bridge Mode to Transparent Mode
This comparison of L2 Bridge Mode to Transparent Mode contains the following sections:
While Transparent Mode allows a security appliance running SonicOS to be introduced into an existing network without the need for re-addressing, it presents a certain level of disruptiveness, particularly with regard to ARP, multiple subnets, and non-IPv4 traffic types. Consider the diagram below, in a scenario where a Transparent Mode SonicWALL appliance has just been added to the network with a goal of minimally disruptive integration, particularly:
ARP in Transparent Mode
ARP – Address Resolution Protocol (the mechanism by which unique hardware addresses on network interface cards are associated to IP addresses) is proxied in Transparent Mode. If the Workstation on Server on the left had previously resolved the Router (192.168.0.1) to its MAC address 00:99:10:10:10:10, this cached ARP entry would have to be cleared before these hosts could communicate through the SonicWALL. This is because the SonicWALL proxies (or answers on behalf of) the gateway’s IP (192.168.0.1) for hosts connected to interfaces operating in Transparent Mode. So when the Workstation at the left attempts to resolve 192.168.0.1, the ARP request it sends is responded to by the SonicWALL with its own X0 MAC address (00:06:B1:10:10:10).
The SonicWALL also proxy ARPs the IP addresses specified in the Transparent Range (192.168.0.100 to 192.168.0.250) assigned to an interface in Transparent Mode for ARP requests received on the X1 (Primary WAN) interface. If the Router had previously resolved the Server (192.168.0.100) to its MAC address 00:AA:BB:CC:DD:EE, this cached ARP entry would have to be cleared before the router could communicate with the host through the SonicWALL. This typically requires a flushing of the router’s ARP cache either from its management interface or through a reboot. Once the router’s ARP cache is cleared, it can then send a new ARP request for 192.168.0.100, to which the SonicWALL will respond with its X1 MAC 00:06:B1:10:10:11.
Multiple Subnets in Transparent Mode
It is also common for larger networks to employ multiple subnets, be they on a single wire, multiple wires, or some combination. While Transparent Mode is capable of supporting multiple subnets through the use of Static ARP and Route entries, as the Technote http://www.sonicwall.com/us/support/2134_3468.html describes, it is not an effortless process.
Non-IPv4 Traffic in Transparent Mode
Transparent Mode will drop (and generally log) all non-IPv4 traffic, precluding it from passing other traffic types, such as IPX, or unhandled IP types.
L2 Bridge Mode addresses these common Transparent Mode deployment issues and is described in the following section.
Simple Transparent Mode Topology
ARP in L2 Bridge Mode
L2 Bridge Mode employs a learning bridge design where it will dynamically determine which hosts are on which interface of an L2 Bridge (referred to as a Bridge-Pair). ARP is passed through natively, meaning that a host communicating across an L2 Bridge will see the actual host MAC addresses of their peers. For example, the Workstation communicating with the Router (192.168.0.1) will see the router as 00:99:10:10:10:10, and the Router will see the Workstation (192.168.0.100) as 00:AA:BB:CC:DD:EE.
This behavior allows for a SonicWALL operating in L2 Bridge Mode to be introduced into an existing network with no disruption to most network communications other than that caused by the momentary discontinuity of the physical insertion.
Please note that stream-based TCP protocols communications (for example, an FTP session between a client and a server) will need to be re-established upon the insertion of an L2 Bridge Mode SonicWALL. This is by design so as to maintain the security afforded by stateful packet inspection (SPI); since the SPI engine can not have knowledge of the TCP connections which pre-existed it, it will drop these established packets with a log event such as TCP packet received on non-existent/closed connection; TCP packet dropped.
L2 Bridge IP Packet Path
The following sequence of events describes the above flow diagram:
It is possible to construct a Firewall Access Rule to control any IP packet by any of its IP elements, such as source IP, destination IP, or service type. If the packet is disallowed, it will be dropped and logged. If the packet is allowed, it will continue.
Multiple Subnets in L2 Bridge Mode
L2 Bridge Mode is capable of handling any number of subnets across the bridge, as described above. The default behavior is to allow all subnets, but Access Rules can be applied to control traffic as needed.
Non-IPv4 Traffic in L2 Bridge Mode
Unsupported traffic will, by default, be passed from one L2 Bridge interface to the Bridge-Partner interface. This allows the SonicWALL to pass other traffic types, including LLC packets such as Spanning Tree, other EtherTypes, such as MPLS label switched packets (EtherType 0x8847), Appletalk (EtherType 0x809b), and the ever-popular Banyan Vines (EtherType 0xbad). These non-IPv4 packets will only be passed across the Bridge, they will not be inspected or controlled by the packet handler. If these traffic types are not needed or desired, the bridging behavior can be changed by enabling the Block all non-IPv4 traffic option on the Secondary Bridge Interface configuration page.
Comparison of L2 Bridge Mode to Transparent Mode
Attribute
Layer 2 Bridge Mode
Transparent Mode
Layer of Operation
Layer 2 (MAC)
Layer 3 (IP)
ARP behavior
ARP (Address Resolution Protocol) information is unaltered. MAC addresses natively traverse the L2 bridge. Packets that are destined for SonicWALL’s MAC addresses will be processed, others will be passed, and the source and destinations will be learned and cached.
ARP is proxied by the interfaces operating in Transparent Mode.
Path determination
Hosts on either side of a Bridge-Pair are dynamically learned. There is no need to declare interface affinities.
The Primary WAN interface is always the master ingress/egress point for Transparent mode traffic, and for subnet space determination. Hosts transparently sharing this subnet space must be explicitly declared through the use of Address Object assignments.
Maximum interfaces
Two interfaces, a Primary Bridge Interface and a Secondary Bridge Interface.
Two or more interfaces. The master interface is always the Primary WAN. There can be as many transparent subordinate interfaces as there are interfaces available.
Maximum pairings
The maximum number of Bridge-Pairs allowed is limited only by available physical interfaces. For example, a PRO 2040 could have two Bridge-Pairs (X1+X0, X2+X3), and a PRO 4100 could have five Bridge-Pairs, etc. This can be described as “many One-to-One pairings”.
Transparent Mode only allows the Primary WAN subnet to be spanned to other interfaces, although it allows for multiple interfaces to simultaneously operate as transparent partners to the Primary WAN. This can be described as “a single One-to-One” or “a single One-to-Many pairing”.
Zone restrictions
The Primary Bridge Interface can be Untrusted, Trusted, or Public. The Secondary Bridge Interface can be Trusted or Public.
Interfaces in a Transparent Mode pair must consist of one Untrusted interface (the Primary WAN, as the master of the pair’s subnet) and one or more Trusted/Public interface (e.g. LAN or DMZ).
Subnets supported
Any number of subnets is supported. Firewall Access Rules can be written to control traffic to/from any of the subnets as needed.
In its default configuration, Transparent Mode only supports a single subnet (that which is assigned to, and spanned from the Primary WAN). It is possible to manually add support for additional subnets through the use of ARP entries and routes.
Non-IPv4 Traffic
All non-IPv4 traffic, by default, is bridged from one Bridge-Pair interface to the Bridge-Partner interface, unless disabled on the Secondary Bridge Interface configuration page. This includes IPv6 traffic, STP (Spanning Tree Protocol), and unrecognized IP types.
Non IPv4 traffic is not handled by Transparent Mode, and is dropped and logged.
PortShield interfaces
PortShield interfaces cannot be assigned to either interface of an L2 Bridge Pair.
PortShield interfaces may be assigned a Transparent Mode range.
Dynamic addressing
Although a Primary Bridge Interface may be assigned to the WAN zone, only static addressing is allowable for Primary Bridge Interfaces.
Although Transparent Mode employs the Primary WAN as a master interface, only static addressing is allowable for Transparent Mode.
VPN support
VPN operation is supported with one additional route configured. See the VPN Integration with Layer 2 Bridge Mode section for details.
VPN operation is supported with no special configuration requirements.
DHCP support
DHCP can be passed through a Bridge-Pair.
Interfaces operating in Transparent Mode can provide DHCP services, or they can pass DHCP using IP Helper.
Routing and NAT
Traffic will be intelligently routed in/out of the L2 Bridge-Pair from/to other paths. By default, traffic will not be NATed from one Bridge-Pair interface to the Bridge-Partner, but it can be NATed to other paths, as needed. Custom routes and NAT policies can be added as needed.
Traffic will be intelligently routed from/to other paths. By default, traffic will not be NATed from/to the WAN to/from Transparent Mode interface, but it can be NATed to other paths, as needed. Custom routes and NAT policies can be added as needed.
Stateful Packet Inspection
Full stateful packet inspection will be applied to all IPv4 traffic traversing the L2 Bridge for all subnets.
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.
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.
Benefits of Transparent Mode over L2 Bridge Mode
The following are circumstances in which Transparent Mode might be preferable over L2 Bridge Mode:
Comparing L2 Bridge Mode to the CSM Appliance
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 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.
L2 Bridge Path Determination
Packets received by the SonicWALL on Bridge-Pair interfaces must be forwarded along to the appropriate and optimal path toward their destination, whether that path is the Bridge-Partner, some other physical or sub interface, or a VPN tunnel. Similarly, packets arriving from other paths (physical, virtual or VPN) bound for a host on a Bridge-Pair must be sent out over the correct Bridge-Pair interface. The following summary describes, in order, the logic that is applied to path determinations for these cases:
In this last case, since the destination is unknown until after an ARP response is received, the destination zone also remains unknown until that time. This precludes the SonicWALL from being able to apply the appropriate Access Rule until after path determination is completed. Upon completion, the correct Access Rule will be applied to subsequent related traffic.
With regard to address translation (NAT) of traffic arriving on an L2 Bridge-Pair interface:
L2 Bridge Interface Zone Selection
Bridge-Pair interface zone assignment should be done according to your network’s traffic flow requirements. Unlike Transparent Mode, which imposes a system of “more trusted to less trusted” by requiring that the source interface be the Primary WAN, and the transparent interface be Trusted or Public, L2 Bridge mode allows for greater control of operational levels of trust. Specifically, L2 Bridge Mode allows for the Primary and Secondary Bridge Interfaces to be assigned to the same or different zones (e.g. LAN+LAN, LAN+DMZ, WAN+CustomLAN, etc.) This will affect not only the default Access Rules that are applied to the traffic, but also the manner in which Deep Packet Inspection security services are applied to the traffic traversing the bridge. Important areas to consider when choosing and configuring interfaces to use in a Bridge-Pair are Security Services, Access Rules, and WAN connectivity:
Security Services Directionality
As it will be one of the primary employments of L2 Bridge mode, understanding the application of security services is important to the proper zone selection for Bridge-Pair interfaces. Security services applicability is based on the following criteria:
Based on the source and destination, the packet’s directionality is categorized as either Incoming or Outgoing, (not to be confused with Inbound and Outbound) where the following criteria is used to make the determination:
Dest
Src
Untrusted
Public
Wireless
Encrypted
Trusted
Multicast
Untrusted
Incoming
Incoming
Incoming
Incoming
Incoming
Incoming
Public
Outgoing
Outgoing
Outgoing
Incoming
Incoming
Incoming
Wireless
Outgoing
Outgoing
Trust
Trust
Trust
Incoming
Encrypted
Outgoing
Outgoing
Trust
Trust
Trust
Outgoing
Trusted
Outgoing
Outgoing
Trust
Trust
Trust
Outgoing
Table data is subject to change.
In addition to this categorization, packets traveling to/from zones with levels of additional trust, which are inherently afforded heightened levels of security (LAN|Wireless|Encrypted<-->LAN|Wireless|Encrypted) are given the special Trust classification. Traffic with the Trust classification has all signatures applied (Incoming, Outgoing, and Bidirectional).
Access Rule Defaults
Default, zone-to-zone Access Rules. The default Access Rules should be considered, although they can be modified as needed. The defaults are as follows:
WAN Connectivity
Internet (WAN) connectivity is required for stack communications, such as licensing, security services signature downloads, NTP (time synchronization), and CFS (Content Filtering Services). At present, these communications can only occur through the Primary WAN interface. If you require these types of communication, the Primary WAN should have a path to the Internet. Whether or not the Primary WAN is employed as part of a Bridge-Pair will not affect its ability to provide these stack communications (for example on a PRO 4100, X0+X2 and X3+X4 could be used to create two Bridge-Pairs separate of X1).
Note: If Internet connectivity is not available, licensing can be performed manually and signature updates can also be performed manually (http://www.sonicwall.com/us/support/2134_4170.html).
Sample Topologies
The following are sample topologies depicting common deployments. Inline Layer 2 Bridge Mode represents the addition of a SonicWALL security appliance to provide UTM services in a network where an existing firewall is in place. Perimeter Security represents the addition of a SonicWALL security appliance in pure L2 Bridge mode to an existing network, where the SonicWALL is placed near the perimeter of the network. Internal Security represents the full integration of a SonicWALL security appliance in mixed-mode, where it provides simultaneous L2 bridging, WLAN services, and NATed WAN access. Layer 2 Bridge Mode with High Availability represents the mixed-mode scenario where the SonicWALL HA pair provide high availability along with L2 bridging. Layer 2 Bridge Mode with SSL VPN represents the scenario where a SonicWALL Aventail SSL VPN or SonicWALL SSL VPN Series appliance is deployed in conjunction with L2 Bridge mode.
See the following sections:
Wireless Layer 2 Bridge
In wireless mode, after bridging the wireless (WLAN) interface to a LAN or DMZ zone, the WLAN zone becomes the secondary bridged interface, allowing wireless clients to share the same subnet and DHCP pool as their wired counterparts
To configure a WLAN to LAN Layer 2 interface bridge:
Note: Although a general rule is automatically created to allow traffic between the WLAN zone and your choosen bridged interface, WLAN zone type security properties still apply. Any specific rules must be manually added.
Inline Layer 2 Bridge Mode
This method is useful in networks where there is an existing firewall that will remain in place, but you wish to utilize the SonicWALL’s UTM services without making major changes to the network. By placing the SonicWALL in Layer 2 Bridge mode, the X0 and X1 interfaces become part of the same broadcast domain/network (that of the X1 WAN interface).
This example refers to a SonicWALL UTM appliance installed in a Hewlitt Packard ProCurve switching environment. SonicWALL is a member of HP’s ProCurve Alliance – more details can be found at the following location:http://h20195.www2.hp.com/v2/GetPDF.aspx/4AA1-9147ENUC.pdf
HP’s ProCurve Manager Plus (PCM+) and HP Network Immunity Manager (NIM) server software packages can be used to manage the switches as well as some aspects of the SonicWALL UTM appliance.
To configure the SonicWALL appliance for this scenario, navigate to the Network > Interfaces page and click on the configure icon for the X0 LAN interface. On the X0 Settings page, set the IP Assignment to ‘Layer 2 Bridged Mode’ and set the Bridged To: interface to ‘X1’. Also make sure that the interface is configured for HTTP and SNMP so it can be managed from the DMZ by PCM+/NIM. Click OK to save and activate the change.
You will also need to make sure to modify the firewall access rules to allow traffic from the LAN to WAN, and from the WAN to the LAN, otherwise traffic will not pass successfully. You may also need to modify routing information on your firewall if your PCM+/NIM server is placed on the DMZ.
Perimeter Security
The following diagram depicts a network where the SonicWALL is added to the perimeter for the purpose of providing security services (the network may or may not have an existing firewall between the SonicWALL and the router).
In this scenario, everything below the SonicWALL (the Primary Bridge Interface segment) will generally be considered as having a lower level of trust than everything to the left of the SonicWALL (the Secondary Bridge Interface segment). For that reason, it would be appropriate to use X1 (Primary WAN) as the Primary Bridge Interface.
Traffic from hosts connected to the Secondary Bridge Interface (LAN) would be permitted outbound through the SonicWALL to their gateways , while traffic from the Primary Bridge Interface (WAN) would, by default, not be permitted inbound.
If there were public servers, for example, a mail and Web server, on the Secondary Bridge Interface (LAN) segment, an Access Rule allowing WAN->LAN traffic for the appropriate IP addresses and services could be added to allow inbound traffic to those servers.
Internal Security
This diagram depicts a network where the SonicWALL will act as the perimeter security device and secure wireless platform. Simultaneously, it will provide L2 Bridge security between the workstation and server segments of the network without having to readdress any of the workstation or servers.
This typical inter-departmental Mixed Mode topology deployment demonstrates how the SonicWALL can simultaneously Bridge and route/NAT. Traffic to/from the Primary Bridge Interface (Server) segment from/to the Secondary Bridge Interface (Workstation) segment will pass through the L2 Bridge.
Since both interfaces of the Bridge-Pair are assigned to a Trusted (LAN) zone, the following will apply:
Consider, for the point of contrast, what would occur if the X2 (Primary Bridge Interface) was instead assigned to a Public (DMZ) zone: All the Workstations would be able to reach the Servers, but the Servers would not be able to initiate communications to the Workstations. While this would probably support the traffic flow requirements (i.e. Workstations initiating sessions to Servers), it would have two undesirable effects:
For detailed instructions on configuring interfaces in Layer 2 Bridge Mode, see Configuring Layer 2 Bridge Mode
Layer 2 Bridge Mode with SSL VPN
This sample topology covers the proper installation of a SonicWALL UTM device into your existing SonicWALL EX-Series SSL VPN or SonicWALL SSL VPN networking environment. By placing the UTM appliance into Layer 2 Bridge Mode, with an internal, private connection to the SSL VPN appliance, you can scan for viruses, spyware, and intrusions in both directions. In this scenario the SonicWALL UTM appliance is not used for security enforcement, but instead for bidirectional scanning, blocking viruses and spyware, and stopping intrusion attempts. When programmed correctly, the UTM appliance will not interrupt network traffic, unless the behavior or content of the traffic is determined to be undesirable. Both one- and two-port deployments of the SonicWALL UTM appliance are covered in this section.
WAN to LAN Access Rules
Because the UTM appliance will be used in this deployment scenario only as an enforcement point for anti-virus, anti-spyware and intrusion prevention, its existing security policy must be modified to allow traffic to pass in both directions between the WAN and LAN.
On the Firewall > Access Rules page, click the Configure icon for the intersection of WAN to LAN traffic. Click the Configure icon next to the default rule that implicitly blocks uninitiated traffic from the WAN to the LAN.
In the Edit Rule window, select Allow for the Action setting, and then click OK.
Configure the Network Interfaces and Activate L2B Mode
In this scenario the WAN interface is used for the following:
The LAN interface on the UTM appliance is used to monitor the unencrypted client traffic coming from the external interface of the SSL VPN appliance. This is the reason for running in Layer 2 Bridge Mode (instead of reconfiguring the external interface of the SSL VPN appliance to see the LAN interface as the default route).
On the Network > Interfaces page of the SonicOS management interface, click the Configure icon for the WAN interface, and then assign it an address that can access the Internet so that the appliance can obtain signature updates and communicate with NTP.
The gateway and internal/external DNS address settings will match those of your SSL VPN appliance:
For the Management setting, select the HTTPS and Ping check boxes. Click OK to save and activate the changes.
To configure the LAN interface settings, navigate to the Network > Interfaces page and click the Configure icon for the LAN interface.
For the IP Assignment setting, select Layer 2 Bridged Mode. For the Bridged to setting, select X1.
Click OK to save and activate the change. You may be automatically disconnected from the UTM appliance’s management interface. You can now disconnect your management laptop or desktop from the UTM appliance’s X0 interface and power the UTM appliance off before physically connecting it to your network.
Install the SonicWALL UTM appliance between the network and SSL VPN appliance
Regardless of your deployment method (single- or dual-homed), the SonicWALL UTM appliance should be placed between the X0/LAN interface of the SSL VPN appliance and the connection to your internal network. This allows the device to connect out to SonicWALL’s licensing and signature update servers, and to scan the decrypted traffic from external clients requesting access to internal network resources.
If your SSL VPN appliance is in two-port mode behind a third-party firewall, it is dual-homed. To connect a dual-homed SSL VPN appliance, follow these steps:
If your SSL VPN appliance is in one-port mode in the DMZ of a third-party firewall, it is single-homed. To connect a single-homed SSL VPN appliance, follow these steps:
Configure or verify settings
From a management station inside your network, you should now be able to access the management interface on the UTM appliance using its WAN IP address.
Make sure that all security services for the SonicWALL UTM appliance are enabled. See Licensing Services and Activating UTM Services on Each Zone.
SonicWALL Content Filtering Service must be disabled before the device is deployed in conjunction with a SonicWALL Aventail SSL VPN appliance. On the Network > Zones page, click Configure next to the LAN (X0) zone, clear the Enforce Content Filtering Service check box and then click OK.
If you have not yet changed the administrative password on the SonicWALL UTM appliance, you can do so on the System > Administration page.
To test access to your network from an external client, connect to the SSL VPN appliance and log in. Once connected, attempt to access to your internal network resources. If there are any problems, review your configuration and see the Configuring the Common Settings for L2 Bridge Mode Deployments section.
setting is known as Captive-Bridge Mode.)