Security Zones and Interfaces
Learn about security zones and how to assign one or more interfaces on SRX1600, SRX4120, and SRX4300 Firewalls.
A security zone is a logical grouping of network segments that share the same security requirements. Security policies control traffic between zones and regulate inbound and outbound communication.
Security zones define parameters such as host-inbound traffic settings, screens, address books, TCP RST behavior, and member interfaces. You can configure interfaces with IPv4 addresses, IPv6 addresses, or both. By default, interfaces are placed in the null zone and do not pass traffic until the interfaces are explicitly assigned to a security zone.
You can define multiple security zones and assign one or more interfaces to each zone based on your network requirements.
set interfaces ge-0/1/0 unit 0 family inet address 203.0.113.1/24 set interfaces ge-0/1/0 unit 0 family inet6 address 2001:db8:1::1/64 set security zones security-zone ABC interfaces ge-0/1/0 set security zones security-zone ABC host-inbound-traffic system-services ping set security zones security-zone ABC host-inbound-traffic system-services ike set security zones security-zone ABC host-inbound-traffic system-services ssh set security zones security-zone ABC host-inbound-traffic protocols ospf
The security zone configuration workflow is similar across the SRX1600, SRX4120, and SRX4300 Firewalls. However, consider the following platform-specific factors:
- Interface naming and types vary by platform (for example,
et-,xe-,ge-, ormge-interfaces depending on hardware). - Port density and hardware layout differ across firewalls.
The number of interfaces you can assign to a single security zone is subject to platform-specific constraints and Junos OS version limits. The maximum limits vary by Junos OS version, deployment scenario, and any platform-specific scaling enhancements.
Always refer to the official Junos OS release notes and product documentation for your exact software version and platform to confirm the supported interface-per-zone limits. For large-scale, multi tenant, or complex security zone deployments, especially with numerous VLANs or logical interfaces, verify that the Junos OS version and hardware resources align with your interface and zone requirements to avoid configuration or performance issues.