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New and Changed Features


This section describes new features as well as enhancements to existing features starting in Junos OS Release 18.3R1 for cSRX support.

New Features in Junos OS Release 18.3R1 for cSRX

There are no new features in Junos OS Release 18.3R1 for the cSRX.

cSRX Architecture Illustration

cSRX Architecture

Figure 1 is a high-level illustration of the cSRX architecture and Figure 2 is a high-level illustration of a cSRX compute node in a Contrail Networking cloud environment.

For details about the cSRX architecture, see the Overview topic in cSRX Deployment Guide for Bare-Metal Linux Server and cSRX Deployment Guide for Contrail.

Figure 1: cSRX Architecture

cSRX Architecture
Figure 2: cSRX Architecture in Contrail

cSRX Architecture in Contrail

Supported Features

The cSRX Container Firewall inherits many of the branch SRX Series Junos OS features. This topic outlines the SRX series features supported by cSRX along with the features that are not applicable in a containerized environment.

SRX Series Features Supported on cSRX

Table 1 provides a high-level summary of the feature categories supported on cSRX and any feature considerations.

To determine the Junos OS features supported on cSRX, use the Juniper Networks Feature Explorer, a Web-based application that helps you to explore and compare Junos OS feature information to find the right software release and hardware platform for your network. See Feature Explorer.

Table 1: SRX Series Features Supported on cSRX



Application Firewall (AppFW)

Application Firewall Overview

Application Identification (AppID)

Understanding Application Identification Techniques

Application Tracking (AppTrack)

Understanding AppTrack

Basic firewall policy

Understanding Security Basics

Brute force attack mitigation

Central management

CLI only. No J-Web support.

DDoS protection

DoS Attack Overview

DoS protection

DoS Attack Overview


Two revenue network interfaces (eth1, and eth2).

Network Interfaces

Intrusion Detection and Prevention (IDP)

For SRX Series IPS configuration details, see:

Understanding Intrusion Detection and Prevention for SRX Series

IPv4 and IPv6

Understanding IPv4 Addressing

Understanding IPv6 Address Space

Jumbo frames

Understanding Jumbo Frames Support for Ethernet Interfaces

Malformed packet protection

Network Address Translation (NAT)

For SRX Series NAT configuration details, see:

Introduction to NAT


Basic Layer 3 forwarding with VLANs.

Layer 2 through 3 forwarding functions: secure-wire forwarding or static routing forwarding

SYN cookie protection

Understanding SYN Cookie Protection

User Firewall

For SRX Series user firewall configuration details, see:

Overview of Integrated User Firewall

Unified Threat Management (UTM)

For SRX Series UTM configuration details, see:

Unified Threat Management Overview

For SRX Series UTM antispam configuration details, see:

Antispam Filtering Overview

Zones and zone-based IP spoofing

Understanding IP Spoofing

SRX Series Features Not Supported on cSRX

Table 2 lists SRX Series features that are not applicable in a containerized environment, that are not currently supported, or that have qualified support on cSRX.

Table 2: SRX Series Features Not Supported on cSRX


SRX Series Feature

Application Layer Gateways

Avaya H.323

Authentication with IC Series Devices

Layer 2 enforcement in UAC deployments

Note: UAC-IDP and UAC-UTM also are not supported.

Class of Service

High-priority queue on SPC


Data Plane Security Log Messages (Stream Mode)

TLS protocol

Diagnostics Tools

Flow monitoring cflowd version 9

Ping Ethernet (CFM)

Traceroute Ethernet (CFM)

DNS Proxy

Dynamic DNS

Ethernet Link Aggregation

LACP in standalone or chassis cluster mode

Layer 3 LAG on routed ports

Static LAG in standalone or chassis cluster mode

Ethernet Link Fault Management

Physical interface (encapsulations)





Interface family

ccc, tcc


Flow-Based and Packet-Based Processing

End-to-end packet debugging

Network processor bundling

Services offloading


Aggregated Ethernet interface

IEEE 802.1X dynamic VLAN assignment

IEEE 802.1X MAC bypass

IEEE 802.1X port-based authentication control with multisupplicant support

Interleaving using MLFR


PPP interface

PPPoE-based radio-to-router protocol

PPPoE interface

Promiscuous mode on interfaces

IP Security and VPNs

Acadia - Clientless VPN


Hardware IPsec (bulk crypto) Cavium/RMI

IPsec tunnel termination in routing instances

Multicast for AutoVPN

Suite B implementation for IPsec VPN

IPv6 Support

DS-Lite concentrator (also known as AFTR)

DS-Lite initiator (also known as B4)

Log File Formats for System (Control Plane) Logs

Binary format (binary)




Chassis cluster


Hardware acceleration

High availability


Logical systems


Outbound SSH

Remote instance access




Spotlight Secure integration

USB modem

Wireless LAN



Layer 2 VPNs for Ethernet connections

Network Address Translation

Maximize persistent NAT bindings

Packet Capture

Packet capture

Note: Only supported on physical interfaces and tunnel interfaces, such as gr, ip, and st0. Packet capture is not supported on a redundant Ethernet interface (reth).


BGP extensions for IPv6

BGP Flowspec

BGP route reflector

Bidirectional Forwarding Detection (BFD) for BGP



Layer 3 Q-in-Q VLAN tagging

Transparent Mode


Unified Threat Management

Express AV

Kaspersky AV

Upgrading and Rebooting


Boot instance configuration

Boot instance recovery

Dual-root partitioning

OS rollback

User Interfaces


SRC application

Junos Space Virtual Director

Changes in Behavior and Syntax

This section lists the changes in behavior of Junos OS features and changes from Junos OS Release 18.3R1 for the cSRX. For the most complete and latest information about changes in command behavior and syntax applicable to all SRX Series platforms in Junos OS Release 18.3R1, see Changes in Behavior and Syntax for SRX.

Application System Cache for Application Services (SRX Series, cSRX Instances)

Starting with Junos OS 18.2R1, the default behavior of the ASC has changed as follows:

  • Security services such as security policies, application firewall (AppFW), Juniper Sky ATP, IDP, and UTM do not use the ASC by default.

  • Miscellaneous services such as APBR and AppTrack use the ASC for application identification by default.


The change in the default behavior of the ASC affects the legacy Application Firewall (AppFW) functionality. With the ASC disabled by default for the security services starting in Junos OS Release 18.2 onwards, the AppFW will not use the entries present in the ASC.

You can revert to the ASC behavior as in Junos OS releases prior to 18.2 by using the set services application-identification application-system-cache security-services command.


The SRX Series device may become susceptible to application evasion techniques if the ASC is enabled for security services. We recommend that you enable the ASC only when the performance of the device in its default configuration (disabled for security services) is not sufficient for your specific use case.

Use the following commands to enable or disable the ASC:

  • Enable the ASC for security services:

  • Disable the ASC for miscellaneous services:

  • Disable the enabled ASC for security services:

  • Enable the disabled ASC for miscellaneous services:

You can use the show services application-identification application-system-cache command to verify the status of the ASC.

The following sample output provides the status of the ASC:

user@host>show services application-identification application-system-cache

For Junos OS Release prior to 18.2R1, application caching is turned on by default. You can manually turn this caching off using the CLI.