Zone Based Firewall

In zone-based policy, interfaces are assigned to zones, and inspection policy is applied to traffic moving between the zones and acted on according to firewall rules. A Zone is a group of interfaces that have similar functions or features. It establishes the security borders of a network. A zone defines a boundary where traffic is subjected to policy restrictions as it crosses to another region of a network.

Key Points:

  • A zone must be configured before an interface is assigned to it and an interface can be assigned to only a single zone.

  • All traffic to and from an interface within a zone is permitted.

  • All traffic between zones is affected by existing policies

  • Traffic cannot flow between zone member interface and any interface that is not a zone member.

  • You need 2 separate firewalls to define traffic: one for each direction.

Note

In T2199 the syntax of the zone configuration was changed. The zone configuration moved from zone-policy zone <name> to firewall zone <name>.

Configuration

As an alternative to applying policy to an interface directly, a zone-based firewall can be created to simplify configuration when multiple interfaces belong to the same security zone. Instead of applying rule-sets to interfaces, they are applied to source zone-destination zone pairs.

An basic introduction to zone-based firewalls can be found here, and an example at Zone-Policy example.

Define a Zone

To define a zone setup either one with interfaces or a local zone.

set firewall zone <name> interface <interface>

Set interfaces to a zone. A zone can have multiple interfaces. But an interface can only be a member in one zone.

set firewall zone <name> local-zone

Define the zone as a local zone. A local zone has no interfaces and will be applied to the router itself.

set firewall zone <name> default-action [drop |?reject]

Change the default-action with this setting.

set firewall zone <name> description

Set a meaningful description.

Applying a Rule-Set to a Zone

Before you are able to apply a rule-set to a zone you have to create the zones first.

It helps to think of the syntax as: (see below). The ‘rule-set’ should be written from the perspective of: Source Zone-to->*Destination Zone*

set firewall zone <Destination Zone> from <Source Zone> firewall name <rule-set>
set firewall zone <name> from <name> firewall name <rule-set>
set firewall zone <name> from <name> firewall ipv6-name <rule-set>

You apply a rule-set always to a zone from an other zone, it is recommended to create one rule-set for each zone pair.

set firewall zone DMZ from LAN firewall name LANv4-to-DMZv4
set firewall zone LAN from DMZ firewall name DMZv4-to-LANv4