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Junos OS Release Notes for EX Series Switches


These release notes accompany Junos OS Release 18.4R1 for the EX Series. They describe new and changed features, limitations, and known and resolved problems in the hardware and software.

You can also find these release notes on the Juniper Networks Junos OS Documentation webpage, located at

New and Changed Features

This section describes the new features and enhancements to existing features in Junos OS Release 18.4R1 for the EX Series.


The following EX Series switches are supported in Release 18.4R1: EX2300, EX3400, EX4300, EX4600-40F, EX9200, EX9204, EX9208, EX9214, EX9251, and EX9253.


  • 2-port QSFP+/1-port QSFP28 uplink module (EX4300-48MP and EX4300-48MP-S switches) —Starting with Junos OS Release 18.4R1, EX4300-48MP and EX4300-48MP-S switches support an uplink module with two QSFP+ ports and one QSFP28 port.

Authentication, Authorization and Accounting (AAA) (RADIUS)

  • Support for password change policy enhancement (EX Series)—Starting in Junos OS Release 18.4R1, the Junos OS password change policy for local user accounts is enhanced to comply with additional password policies. As part of the policy improvement, you can configure the following:

    • maximum-lifetime-value—The maximum duration of a password. The password expires after the maximum is reached.

    • minimum-lifetime-value—The minimum duration of a password. You cannot change the password until the minimum duration is reached.

    [See password.]


  • Support for graceful restart on EVPN-VXLAN (EX9200, QFX Series, and MX Series)—Starting in Junos OS Release 18.4R1, Junos OS supports graceful restart on EVPN-VXLAN on EX9200 and QFX Series switches and MX Series Routers. Graceful restart allows the device to recover from a routing process restart or Routing Engine switchover without nonstop active routing (NSR) enabled.

    [See NSR and Unified ISSU Support for EVPN Overview.]

  • Support for VMTO for ingress traffic (EX9200)—Starting in Junos OS Release 18.4R1, you can configure a leaf or spine device that is configured as a Layer 3 gateway to support virtual machine traffic optimization (VMTO) for ingress traffic. VMTO eliminates the unnecessary ingress routing to default gateways when a virtual machine is moved from one data center to another.

    To enable VMTO, configure remote-ip-host routes at the [edit routing-instances routing-instance-name protocols evpn] hierarchy level. You can also filter out the unwanted routes by configuring an import policy under the remote-ip-host routes option.

    [See Configuring EVPN Routing Instances.]

  • Support for multihomed proxy advertisement (EX9200)—Starting in Junos OS Release 18.4R1, Junos OS now provides enhanced support to proxy advertise the MAC address and IP route entry from all leaf devices that are multihomed to a customer edge (CE) device. Using proxy advertisement prevents traffic loss when one of the connections to the leaf device fails. To support the multihomed proxy advertisement, all multihomed provider edge (PE) devices should have the same multihomed proxy advertisement bit value. The multihomed proxy advertisement feature is enabled by default, and Junos OS uses the default multihomed proxy advertisement bit value of 0x20.

    [See EVPN Multihoming Overview.]

Interfaces and Chassis

  • Support for uplink module with two 40-Gigabit Ethernet ports and one 100-Gigabit Ethernet port (EX4300-48MP)—Starting with Junos OS Release 18.4R1, the 2-port QSFP+/1-port QSFP28 uplink module on EX4300-48MP switches can be configured to operate either two 40-Gigabit Ethernet ports or one 100-Gigabit Ethernet port. By default, the uplink module operates only the two 40-Gbps ports. To enable 100-Gbps speed, issue the set chassis fpc 0 pic 2 port 0 speed 100g command. The uplink module then enables the 100-Gigabit Ethernet port and disables the adjacent 40-Gigabit Ethernet ports.

    • You can install the 2-port QSFP+/1-port QSFP28 uplink module only in PIC slot 2 on the switch.

    • You can configure 100-Gbps speed only on port 0 of PIC 2 (which is the uplink module slot on the switch).

    You can also channelize 40-Gigabit Ethernet interfaces, to four independent 10-Gigabit Ethernet interfaces using breakout cables.

    [See Setting the Mode on 2-port QSFP+/1-port QSFP28 Uplink Module (CLI Procedure).]

Junos Telemetry Interface

  • Packet Forwarding Engine and Routing Engine sensor support for Junos Telemetry Interface (JTI) (EX4600 switches)—Starting in Junos OS Release 18.4R1, JTI supports Packet Forwarding Engine and Routing Engine statistics for EX4600 switches:

    The following Routing Engine statistics are supported through JTI:

    • LACP state export

    • Chassis environmentals export

    • Network discovery chassis and components

    • LLDP export and LLDP model

    • BGP peer information (RPD)

    • RSVP interface export

    • RPD task memory utilization export

    • LSP event export

    • Network Discovery ARP table state

    • Network Discovery NDP table state

    The following Packet Forwarding Engine statistics are supported through JTI:

    • Congestion and latency monitoring

    • Logical interface

    • Filter

    • Physical interface

    • LSP

    • NPU/LC memory

    • Network Discovery NDP table state

    To provision a sensor to export data through gRPC, use the telemetrySubscribe RPC to specify telemetry parameters. Streaming telemetry data through gRPC also requires the OpenConfig for Junos OS module. Starting in Junos OS Release 18.3R1, OpenConfig and Network Agent packages are bundled into the Junos OS image by default. Both packages support the Junos Telemetry Interface (JTI).

    [See Configuring a Junos Telemetry Interface Sensor (CLI Procedure), Configure a Telemetry Sensor in Junos and Guidelines for gRPC Sensors (Junos Telemetry Interface).]


  • Multicast VLAN registration (MVR) (EX2300 and EX3400 switches and Virtual Chassis)—Starting in Junos OS Release 18.4R1, EX2300 and EX3400 switches and Virtual Chassis support multicast VLAN registration (MVR). MVR efficiently distributes IPTV multicast streams across an Ethernet ring-based Layer 2 network, reducing the bandwidth required for this traffic by using a multicast VLAN (M-VLAN) over which multicast traffic is forwarded to interested listeners on other VLANs that are configured as MVR receiver VLANs. You can configure MVR at the [edit protocols igmp-snooping vlan vlan-name data-forwarding] source and receiver hierarchy levels, and use the show igmp snooping data-forwarding CLI command to view configured M-VLAN and MVR receiver VLAN associations.

    [See Understanding Multicast VLAN Registration.]

Port Security

  • Support for DHCP snooping and other access port security features on private VLANs (EX2300 and EX3400 switches and Virtual Chassis)—Starting in Junos OS Release 18.4R1, you can enable Dynamic Host Configuration Protocol (DHCP) snooping for security purposes on access ports that are in a private VLAN (P-VLAN). You can also protect those ports with DHCP options, dynamic ARP inspection (DAI), IP source guard, and neighbor discovery inspection.

    PVLANs provide Layer 2 isolation between ports within a VLAN, splitting a broadcast domain into multiple discrete broadcast subdomains by creating secondary VLANs. PVLANs are useful for restricting the flow of broadcast and unknown unicast traffic and for limiting the communication between known hosts.

    Ethernet LANs are vulnerable to attacks such as address spoofing (forging) and Layer 2 denial of service (DoS) on network devices. The following port security features help protect access ports on your device against loss of information and productivity that such attacks can cause:

    • DHCP snooping—Filters and blocks ingress DHCP server messages on untrusted ports. DHCP snooping builds and maintains a database of DHCP lease information, which is called the DHCP snooping database.

    • DHCPv6 snooping—DHCP snooping for IPv6.

    • DHCP option 82—Also known as the DHCP Relay Agent Information option. This option helps protect the switch against attacks such as spoofing of IP addresses and MAC addresses and DHCP IP address starvation.

    • DHCPv6 option 37—Remote ID option for DHCPv6. The option is used to insert information about the network location of the remote host into DHCPv6 packets.

    • DHCPv6 option 18—Circuit ID option for DHCPv6. The option is used to insert information about the client port into DHCPv6 packets.

    • DHCPv6 option 16—Vendor ID option for DHCPv6. The option is used to insert information about the vendor of the client hardware into DHCPv6 packets.

    • DAI—Prevents Address Resolution Protocol (ARP) spoofing attacks. ARP requests and replies are compared against entries in the DHCP snooping database, and filtering decisions are made on the basis of the results of those comparisons.

    • IP source guard—Mitigates the effects of IP address spoofing attacks on the Ethernet LAN. The source IP address in the packet sent from an untrusted access interface is validated against the DHCP snooping database.

    • IPv6 source guard—IP source guard for IPv6.

    • IPv6 neighbor discovery inspection—Prevents IPv6 address spoofing attacks. Neighbor discovery requests and replies are compared against entries in the DHCPv6 snooping database, and filtering decisions are made on the basis of the results of those comparisons.

    [See Putting Access Port Security on Private VLANs.]

  • Untrusted mode on trunk interfaces for DHCP snooping (EX2300, EX3400, EX4300 and EX4600 switches)—Starting in Junos OS Release 18.4R1, you can configure a trunk interface as untrusted for DHCP security. Trunk interfaces in untrusted mode support DHCP snooping and DHCPv6 snooping, dynamic ARP inspection (DAI), and IPv6 neighbor discovery (ND) inspection.

    [See Understanding Trusted and Untrusted Ports.]

Virtual Chassis

  • Virtual Chassis support (EX2300-24MP, EX2300-48MP)—Starting in Junos OS Release 18.4R1, multigigabit EX2300 switches can be interconnected into a Virtual Chassis with other EX2300 model switches as follows:

    • Any combination of up to four EX2300-24MP, EX2300-48MP, EX2300, and EX2300-C switches is supported.

    • You do not need to set mixed mode.

    • Any models of EX2300 switches can be in the master or backup Routing Engine roles.

    • Any 10-Gbps uplink ports installed with SFP+ transceivers can be configured as Virtual Chassis ports (VCPs) to interconnect member switches.

    • Use the same steps as for configuring any other EX2300, EX3400, or EX4300 Virtual Chassis.

    [See Understanding EX Series Virtual Chassis.]

Changes in Behavior and Syntax

This section lists the changes in behavior of Junos OS features and changes in the syntax of Junos OS statements and commands from Junos OS Release 18.4R1 for the EX Series.

Network Management and Monitoring

  • The NETCONF server omits warnings in RPC replies when the rfc-compliant statement is configured and the operation returns <ok/> (EX Series)—Starting in Junos OS Release 18.4R1, when you configure the rfc-compliant statement at the [edit system services netconf] hierarchy level to enforce certain behaviors by the NETCONF server, the server must not return an RPC reply that encloses both an <rpc-error> element and an <ok/> element. If the operation is successful, but the server reply would enclose one or more <rpc-error> elements of severity warning in addition to the <ok/> element, then the warnings are omitted. In earlier releases, or when the rfc-compliant statement is not configured, the NETCONF server might issue an RPC reply that encloses both an <rpc-error> element of severity warning and an <ok/> element.

Known Behavior

This section lists known behavior, system maximums, and limitations in hardware and software in Junos OS Release 18.4R1 for the EX Series.

For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • A few error messages related to the function rt_mesh_group_add_check() are seen during reboot. These errors are harmless. PR1365049

  • Automatic channelisation is not supported for 40GBASE-BXSR, QSFP+40GE-LX4, QSFP-100G-PSM4, and 100GBASE-BXSR optics. PR1366103

  • On the EX4300-MP switch, the et-0/2/* (100-Gigabit Ethernet) interface multicast queue in strict-priority mode gets the priority treatment only across other multicast queues. PR1377692

Class of Service (CoS)

  • On EX4650 switches, if the CoS configurations are modified when egress traffic is shaped at a very low rate (< 50 Mbps), packets might get stuck in the MMU buffers permanently. It might cause ingress or egress traffic drops. When low rate shapers (< 50 Mbps) are applied on egress queues, we recommend you to deactivate shaping before any CoS modification or ensure traffic is stopped before modifying the CoS configuration. PR1367432

Routing Protocols

  • On EX4650 switches, 254 neighbors and 200,000 routes can be scaled for IS-IS v4. Beyond 200,000 routes with 254 neighbors, adjacency flaps and traffic drop will be seen. However, with 40 neighbors, scaling of 351,000 routes is achieved. PR1368106

Known Issues

This section lists the known issues in hardware and software in Junos OS Release 18.4R1 for the EX Series.

For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • Various common situations lead to different views of forwarding information between the kernel and Packet Forwarding Engines. For example, fpc7 KERNEL/PFE APP=NH OUT OF SYNC: error code 3 REASON: NH add received and for a logical interface that does not exist, the error message displayed is ERROR-SPECIFIC INFO: nh_id=562 , type = Hold, ifl index 334 does not exist TYPE-SPECIFIC INFO: none. As such there is no service impact on MPC2 and MPC3 cards. PR1205593

  • If a configuration that takes a Packet Forwarding Engine offline and another configuration that brings the Packet Forwarding Engine back online are committed in quick succession, then Routing Engine-Packet Forwarding Engine out-of-sync errors might be logged in the syslog. Most of the time these are benign errors, but sometimes they might result in Packet Forwarding Engine crashes. PR1232178

  • On EX4600 switches, in some cases, CoS configuration is not properly applied in the Packet Forwarding Engine, leading to unexpected egress traffic drop on some interfaces. PR1329141

  • On an EX2300 switch, the output of the show chassis routing-engine command might display the incorrect value of mac reset for the last reboot reason field. PR1331264

  • On EX4500 switches, the set interfaces interface disable command might not work for SFP+ interface if connected to another vendor's network device. PR1354673

  • The CHASSISD_I2CS_READBACK_ERROR: Readback error from I2C slave for FPC 0 ([0x0, 0x20] -> 0x0) error message is seen when you bring the MIC in MIC slot 1 of the line card online. PR1355942

  • On EX4650 switches, if lcmd is restarted, chassisd core files might be generated with traffic drop for a few seconds. PR1363652

  • The time lapse between interface down interrupt detection to FRR call back is ~148ms on QFX5120 platform, although the in-place update FRR programming completes in 1 ms. The minimum FRR time achieved with this limitation is around 150 ms and maximum is around 275 ms. PR1364244

  • On EX2200, EX3200, EX3300, EX4200, and EX4500 switches, the show interface ge-x/x/x extensive command shows Duplex: Half-duplex in the output when link-mode is set as automatic or is not set (default). This is a display issue and has no service impact. PR1364659

  • The EX4300 Virtual Chassis might fail to register some jnxOperating SNMP OIDs related to the Routing Engines. This behavior is more likely if Virtual Chassis members 0 and 1 (FPC0 and FPC1) are not selected as Routing Engines. PR1368845

  • With swap-out of a Virtual Chassis of QFX5100 to the EX9253 for testing of some heavy multicast, even when the IRB interface comes up, traffic drops might be observed. PR1369099

  • Multicast router advertisement packets coming on a VLAN need to be flooded to interfaces of all FPCs belonging to the same VLAN. Packets when traversing through a HighGig port (that connects different FPCs) need to hit hardware filter to transmit packets to other FPCs. In this state, the filter is not applicable for the HighGig ports, so multicast RA packets do not traverse through other FPCs. PR1370329

  • There are multiple failures when events such as node reboots, ICL flaps, and ICCP flaps occur; and even with enhanced convergence configured there is no guarantee that subsecond convergence will be achieved. PR1371493

  • In EX2300 and EX3400 switches, image upgrade might fail because of an insufficient space issue. PR1376488

  • On EX9200 switches, if the packet-length option is configured under a firewall filter that is applied on the egress interface, such configuration cannot be committed because of commit-check failure. PR1378901

  • After you upgrade the standalone EX4550 switch to Junos OS Release 15.1R6-x, one of the ports on the switch (ge-0/0/22) is does not come up. This problem occurs because MACsec bypass is not set on the port for unknown reason. A workaround is added to enable MACsec bypass if not set during initialization of the physical layer. PR1380991

  • On EX9200 switches, constant memory leak might occur on an FPC, and such a condition might finally lead to memory exhaustion and generation of core files by the FPC. PR1381527

  • If the port number entered for PIC 2 is greater than 2, an error message is displayed. PR1382578

Authentication and Access Control

  • The auth request does not cause the router to send RADIUS request message and displays the following message: Failed to queue the request, will be queued in authd internal queue. PR1366002

  • On EX2200, EX2500, EX3200, EX3300, EX4200, EX4500, EX6200, EX8200 switches in an 802.1X scenario, if the trunk port is used with no-mac-binding configured, a memory leak (125 Bytes per 802.1x event) can be seen. PR1373053

  • DHCPv6 Client is not supported in this release for EX4300-48MP. PR1373691

  • On EX6200 and EX8200 switches with the examine-dhcp configuration enabled, the DHCP packet might be incorrectly flooded and replayed back out of the interface on which it is received: this might lead to incorrect MAC-move errors (on the device connected to the EX6200 or EX8200) and loss of traffic for the client MAC. PR1379936


  • On an EX2300 switch, the IfSpeed and IfHighSpeed MIB values might be incorrectly displayed during an SNMP get operation. PR1326902

  • Junos OS can hang trying to acquire the SMP IPI lock while rebooting when it is running as a VM on Linux and the QEMU hypervisor. PR1359339

  • On EX3400 and EX2300, system time is not retained across switch reboots. PR1397626

Interfaces and Chassis

  • After GRES, the VSTP port cost on aggregated Ethernet interfaces might get changed, leading to a topology change. PR1174213

Layer 2 Features

  • On EX4200, EX3300, EX2200, and EX4500 Virtual Chassis, eswd core files might be observed on the backup Routing Engine. PR1346566

  • The eswd[1200]: ESWD_MAC_SMAC_BRIDGE_MAC_IDENTICAL: Bridge Address Add: XX:XX:db:2b:26:81 SMAC is equal to bridge mac hence don't learn message is seen in the syslog every few minutes on the ERPS owner. Bacause the log is caused by the ERPS PDU in an ERPS setup, you can ignore the message. PR1372422


  • IGMP query packets are duplicated between Layer 2 interfaces with igmp-snooping enabled. PR1391753

Network Management and Monitoring

  • It is a corner scenario where the trace files are not closed correctly that results in stopping of trace write. PR1380764

Platform and Infrastructure

  • Interface ranges for channelized interfaces are not supported on EX9253; you have to configure interfaces individually. PR1350635

  • When we apply any filter on the loopback interface, the other firewall filter for multicast might not work. PR1392082

Routing Protocols

  • On a dual Routing Engine system with GRES and graceful restart enabled, if Bidirectional Forwarding Detection (BFD) with hold-down-interval option is enabled on an external BGP peer, this BGP peer might stay in an idle state after a Routing Engine switchover. PR1324475

  • The mcsnoopd process might crash when all the core-facing interfaces that are part of the Layer 2 domain have flapped and it is attempting to flood a packet received over a customer edge (CE) device interface, over the core-facing interfaces. PR1329694

  • On EX4650 switches, when the UFT profile lpm-profile prefix-65-127-disable or lpm-profile is configured, the command output show pfe route summary hw shows different scale values for the IPv4 and IPv6 LPM routes rather than displaying the supported scale. The supported scale is as follows: lpm-profile prefix-65-127-disable IPv4 <= /32 IPv6 <= /64 IPv6 > /64 Enabled 351K (360,000 approx) 168K (172,000 approx) 0k Disabled 168K (172,000 approx) 64K (65524 approx) 64K (65524 approx) PR1366579

  • On EX4650 switches, when the UFT configuration num-65-127-prefix-4 is scaled with more than 64 prefix IPv6 routes, the show pfe route inet6 hw lpm command output shows only a single IPv6 entry but not the scaled entries. PR1369320

Spanning Tree Protocols

  • In a highly scaled VSTP (3 Interfaces x 253 VLANs) and MSTP configuration, the CPU utilization might increase resulting in the Packet Forwarding Engine getting lesser CPU. This could, in turn, cause IPC connections to be dropped between Virtual Chassis. PR1331858

Resolved Issues

This section lists the issues fixed in the Junos OS Release 18.4R1 for EX Series switches.

For the most complete and latest information about known Junos OS defects, use the Juniper Networks online Junos Problem Report Search application.

General Routing

  • On the EX4300-32F, the MACsec session stays down on 1-Gigabit and 10-Gigabit Ethernet links after certain events, when events are performed with traffic running. PR1299484

  • On EX2300 and EX3400 switches, the bridge ID is assigned to 02:00:00:00:00:10 irrespective of the base-MAC addresses. PR1315633

  • Incorrect value of optical power is displayed. PR1326642

  • On EX3400 and EX2300 switches, a redirect message is sent from the switch even when no-redirect is set for the specified interface. PR1333153

  • The fxpc process might crash after Q-in-Q VLAN is added to or deleted from an interface on EX2300 or EX3400 switches. PR1334850

  • Consideration of relaxing P-VLAN conflict rules during VLAN change for reauthentication and CoA scenarios. PR1346936

  • The 40-Gigabit Ethernet interfaces might not forward traffic. PR1349675

  • On EX2300, EX3400, and EX4300MP switches in a Virtual Chassis setup, dynamic Arp inspection might fail after Virtual Chassis switchover when VSTP is enabled along with no-mac-table-binding. PR1359753

  • The traffic uses the original IRB MAC address if you are configuring a MAC address for an IRB interface. PR1359816

  • On EX2300MP switches, the fan count is wrong in jnxFruName,jnxFilledDescr and jnxContainersCount.4. PR1361025

  • The EX4300-MP MACsec AES-GCM-128-XPN and AES-GCM-256-XPN cipher suites are not supported for MGE ports. PR1362035

  • FPM board status is missing in the SNMP MIB walk result. PR1364246

  • The l2cpd process might crash when you configure MVRP with private VLAN and RSTP interface-all. PR1365937

  • Virtual Chassis split followed by generation of fxpc core files might occur when VLAN members are scaled. PR1369678

  • Unicast ARP packet loop might be observed in a DAI scenario. PR1370607

  • NTP broadcast packets are not forwarded out on Layer 2 ports. PR1371035

  • MAC refresh packet might not be sent out from the new primary link after an RTG failover. PR1372999

  • BOOTP packets might be dropped if BOOTP-support is not enabled at the global level. PR1373807

  • FPC might crash when the output interface flaps with analyzer or sampling configured. PR1374861

  • The port access list group is not properly reallocating the TCAM slices. PR1375022

  • The interface AE480 or above might be in STP discarding state on EX9200 switches. PR1378272

  • On EX4300-48MP, the IP transit traffic hits the lo0 filter. PR1379328

  • All interfaces belonging to a certain FPC might be lost after multiple GRES in Virtual Chassis. PR1379790

  • The 802.1X configuration does not work with Microsoft NPS server. PR1381017

  • On EX4300-48MP, as the session-option configuration under the access profile hierarchy is not applicable for EX Series and QFX Series, do not use that statement and options under it PR1385229

  • On EX9200, a warning message prefer-status-control-active is used with status-control standby is seen whenever you commit a configuration. PR1386479

  • On an EX2300 with Q-in-Q (flexible-vlan-tagging), you are unable to obtain the DHCP IP for the IRB interface after power-cycling the device. PR1387039

  • The smid process might generate core files during sanity script execution on QFX5100 and EX4300. PR1391909


  • Proxy ARP might not work as expected in an EVPN environment. PR1368911

High Availability (HA) and Resiliency

  • The backup Routing Engine might go to database prompt after performing configurations such as remove and restore are performed. PR1269383


  • Core files might be generated upon attempt to commit a configuration. PR1376362

Junos Fusion Enterprise

  • The peer_daemon: bad daemon: scpd error message is seen on EX9251 running Junos OS Releases 18.1R1 and 18.1R2. PR1369646

Layer 2 Features

  • The firewall filter might not work correctly with the match condition of dot1q-tag on an EX Series switch. PR1369592

  • RTG MAC refresh packets are sent out from non-RTG ports if the RTG interface belonging to the Virtual Chassis master flaps. PR1389695

Network Management and Monitoring

  • On EX4600 switches, unsupported CLI configurations and show commands from the cfm hierarchy or sub-hierarchy are allowed. PR1359052

  • While toggling multiple times between baseline and CFM configurations, all 30 CFM sessions are not up. PR1360907

  • The event-policy generated traps are sent with UTC, even though the time zone is defined under the system hierarchy. PR1380777

Platform and Infrastructure

  • Interface flapping is seen on an EX4300 switch. PR1361483

  • Some interfaces cannot be added under the MSTP configuration. PR1363625

  • On EX4300 and EX4600 switches, the l2ald process might crash in an 802.1x scenario. PR1363964

  • The Packet Forwarding Engine might crash if frequent MAC moves are encountered. PR1367141

  • The LLDP TLV with the wrong switch port capabilities might be sent. PR1372966

  • Login lockout might never expire because the timestamps of Lockout start and Lockout end are same. PR1373803

  • On EX4300-48MP, unsupported 1-gigabit optics in the 10-gigabit uplink module might cause interface traffic to be dropped. PR1374390

  • Traffic might be silently discarded with indirect next hop and load balancing. PR1376057

  • The IRB interface does not go down when the master Virtual Chassis is rebooted or halted. PR1381272

  • On the EX4300 switch, if a loss priority value of high is set for multicast packets by a classifier at the ingress interface, the configuration is overridden by the storm-control filter. PR1382893

  • The EX4300 device chooses a wrong bridge ID as the RSTP Bridge ID. PR1383356

  • On EX4300-48MP mixed Virtual Chassis, the Power over Ethernet interface maximum power configuration on a member EX4300 gives an error if the power is configured to be more than 30 W. PR1383717

  • Layer 3 IP route is destroyed after the Layer 2 next hop is changed. PR1389688

Routing Protocols

  • On EX4300-48MP, stale VLAN entries might be seen after a script involving split or merge reboots is run continuously. PR1363739

Documentation Updates

There are no errata or changes in Junos OS Release 18.4R1 documentation for the EX Series switches.

Migration, Upgrade, and Downgrade Instructions

This section contains the upgrade and downgrade support policy for Junos OS for the EX Series. Upgrading or downgrading Junos OS can take several hours, depending on the size and configuration of the network. For information about software installation and upgrade, see the Installation and Upgrade Guide.

Upgrade and Downgrade Support Policy for Junos OS Releases

Support for upgrades and downgrades that span more than three Junos OS releases at a time is not provided, except for releases that are designated as Extended End-of-Life (EEOL) releases. EEOL releases provide direct upgrade and downgrade paths—you can upgrade directly from one EEOL release to the next EEOL release even though EEOL releases generally occur in increments beyond three releases.

You can upgrade or downgrade to the EEOL release that occurs directly before or after the currently installed EEOL release, or to two EEOL releases before or after. For example, Junos OS Releases 17.1, 17.2 and 17.3 are EEOL releases. You can upgrade from Junos OS Release 17.1 to Release 17.2 or from Junos OS Release 17.1 to Release 17.3.

You cannot upgrade directly from a non-EEOL release to a release that is more than three releases ahead or behind. To upgrade or downgrade from a non-EEOL release to a release more than three releases before or after, first upgrade to the next EEOL release and then upgrade or downgrade from that EEOL release to your target release.

For more information about EEOL releases and to review a list of EEOL releases, see

Product Compatibility

Hardware Compatibility

To obtain information about the components that are supported on the devices, and the special compatibility guidelines with the release, see the Hardware Guide for the product.

To determine the features supported on EX Series switches in this release, 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. Find Feature Explorer at

Hardware Compatibility Tool

For a hardware compatibility matrix for optical interfaces and transceivers supported across all platforms, see the Hardware Compatibility tool.

Release History Table
Starting in Junos OS Release 18.3R1, OpenConfig and Network Agent packages are bundled into the Junos OS image by default. Both packages support the Junos Telemetry Interface (JTI).