The distributed firewall (formerly Cascaded Firewall or cfirewall) is a firewall service distributed across multiple NG Firewalls. It is a variant of the regular firewall service, designed to simplify firewall administration by multiple administrators. The distributed firewall is a shared-service and replaces the standalone firewall service. You cannot run a distributed firewall service and a standalone firewall service together on a virtual server. Should both be present the standalone firewall service is automatically deactivated.
Rule Set Structure
The distributed firewall includes all features of the regular firewall service and is created as a shared service in a cluster on the Barracuda NG Control Center. Unlike the standalone firewall service the distributed firewall is organized into three rule sets:
The Global Rules set is evaluated first and contains the global access rules that apply to all NG firewalls using the shared service.
Rule Set Processing
Incoming traffic is matched against the access rules defined in the global rules. All access rules which are the the same for all NG firewalls using the shared service are listed here. The local and special rules contain rules which are specific to the individual NG Firewall. The local and special ruleset are only evaluated if the global ruleset contains a CASCADE access to the rule set. Local and special rules are coequal but both come after global rules. Local and special rules can only work with network objects that have been cascaded to them from the Global Rules section.
The workflow of rules in the Global Rules section is intercepted through cascading to either Special- or Local Rules section. As a final step, from there the workflow is returned to the Global Rules section with a Cascade Back rule.
In the Global Rules section, rules valid for all distributed firewall services bound to a specific cluster service are managed. To simplify maintenance, the global rules node can be linked into a repository. A consistent ruleset architecture can thus be set up and administered.
The Localnet configuration area serves for specification of trusted local networks. These trusted networks are determined for cluster-service-wide use. Every value entered in the Trusted Local Networks dialog results in an entry in the network object localnet in the Global Rules section. There is only one localnet object. Use global firewall objects if you need more granular control.
The Local Rules Section
Use the Locals Rules section to define rules which can generally be applied to servers within a cluster, and should be maintained centrally. Local rules are defined per server-service. They can again contain a complete ruleset with full functionality. The Local Rules section is only applicable, if the Global Rules section allows it, that means it has cascaded the localnet object to the Local Rules section. Do not forget to cascade the object back (Cascade Back), if return to the workflow of the global ruleset is desired.
The Special Rules Section
Use the Special Rules section to define rules which should only apply to specific server services or network segments. Special rules as well are defined per server-service. The Special Rules section is only applicable if the Global Rules section allows it, that means it has cascaded the specialnet object to the Special Rules section. Do not forget to cascade the object back (Cascade Back), if return to the workflow of the global ruleset is desired.
The Specialnet configuration area serves for special networks. Specialnet objects are configured in the distributed firewall Specific node, with server-service-wide validity. Every value in the Special Networks dialog is an entry in the network object Specialnet in the Global Rules section. A specialnet usually is a selective range of IP addresses, needed to configure a subset of rules and at the same time should not be in the Localnet network object. The values entered into the Special Networks configuration window are not visible in the configuration dialog of the network object Specialnet.
Administrator Permission for Distributed Firewalls
Administration rights for distinct distributed firewall administrators can be set through permissions on the firewall related nodes in the configuration tree. Disallowed configuration areas will be set to read-only respectively.
For more information, see Barracuda NG Control Center Admins.
Application Control 2.0 Rulesets in the Distributed Firewall
Application Control 2.0 can be used in the global and local/special rulesets for the distributed firewall. Application rules can be created in the global/ local and specialnet rulesets. You can determine which application rules are used for each ruleset:
- Use both global and local/special application rules (default) – Per default the application rules defined in the ruleset for the matching access rule are used. For example a matching access rule in the Local Rules will evaluate the application rules in defined in Local Rules. If no application rules are defined the application rules from the Global Rules are used instead.
Only use global application rules – If you want to use the application rules defined in the global ruleset exclusively enable Ignore Local/Special Application Ruleset in the Ruleset Setup (Forwarding Firewall > Setup). Application rules in the Local/Special Rules are ignored.
Requirements for Application Control 2.0
- Feature level of the firewall service must be 6.1 to use Application Control 2.0, Virus scanning in the Firewall, ATD, Safe Search, YouTube for Schools and custom block pages.
- SSL Interception and URL Filter will not work on managed Barracuda NG Firewalls F10 and F100/101.
- Barracuda NG Control Center and all managed NG Firewalls using the distributed firewall must run firmware 6.1.0 or higher. If you are upgrading a distributed firewall service (firmware version 5.4.3 or lower), you must run the treemigration script on the command line interface of your NG Control Center to migrate to Application Control 2.0.
Application Control Migration for the Distributed Firewall Service
Migrate a cluster:
treemigration -c -m
Migrate a range:
treemigration -c -m