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Known Limitations

Learn about known limitations in this release 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.


  • After a reboot during recovery process, the ESI LAGs come up before the BGP sessions, and routes or ARP entries are not synchronized. PR1487112

General Routing

  • When the device is up and running for a long time, there is a possibility FS gets bad blocks and it is accumulated. When any change done to it, it reloads and tries to recover the bad blocks from the FS. PR910445

  • Junos OS can hang trying to acquire the SMP IPI lock while rebooting when it is running as a VM on Linux and QEMU hypervisor. Device can be recovered using power-cycle of the device PR1385970

  • On all platforms running Junos OS or Junos OS Evolved, in a Q-in-Q environment, if xSTP is enabled on an interface that has a logical interface with vlan-id-list configured, then, it will only run on those logical interfaces whose vlan-id range includes native-vlan-id configured. All other xSTP will be in discarding state. This might lead to traffic drop. PR1532992

  • Whenever a firewall is configured with action inline monitoring and to count, the corresponding firewall counters will not show any increment in traffic statistics. This limitation is from underlying hardware. PR1542192

  • Inline monitoring security service may not report a IPv4 security violation when traffic is received with source IP address same as destination IP address. This is limitation from Hardware. PR1542213

  • On a virtual chassis, cli command to add license is not available on the backup member. Licenses should be added from the master member only. PR1545075

  • When user issues "request support information" to collect debug data for sharing with Tech Support, commands which are not supported for the platform will display a syntax error message. PR1547835

  • In a Virtual Chassis environment, whenever there is a Link Aggregation Group (LAG) configured with child members from different virtual chassis members, then layer2-header hashing should be used to distribute traffic across the LAG members. Usage of vlan-id based hashing is not recommended and might result in reduced throughput of the LAG. PR1548859

  • Tail drop is seen in WRED configuration statistics. PR1549910

  • Inline-monitoring service supports only upto a maximum of 8 instances. PR1550014

  • VRRP delegate-processing currently not supported on EX4400 Series of switches. PR1552076

  • Packets mirrored through analyzer with ingress and egress interfaces across different virtual chassis members might have an different vlan-id from that of vlan-id of the exiting egress interface. This limitation is from underling hardware. PR1552905

  • License keys should be installed using either operational command or configuration set commands. Same license key should not be added via both operational and set comands. PR1557980

  • "Cattle-Prod daemon received unknown trigger (type Semaphore, id 1)" error messages seen on the VTY when you issue CLI commands to fetch host route scale. No functionality impact is observed. PR1554140

  • Observing traffic drop during ISSU due to LAG interface flap. PR1569578

  • Below is the status of management LED when speed is set to: 1. 10m - Activity LED is not blinking when ping/traffic is runnig (instead it is remaining steady GREEN) 2. 100m - Activity LED is blinking without any ping/traffic. PR1573889

  • License keys should be installed using either operational command or configuration set commands. Same license key should not be added via both operational and set comands. PR1557980

  • On a standalone EX2300-MP device, intermittently you see OSPF neighbourship not established with peer. PR1583966

  • When EX2300-MP in standalone mode is used as a DHCP server, initial set of packets received in the server might get dropped. PR1583983

  • After NSSU or upgrading to Junos OS Release 21.1R1,"timeout waiting for response from fpc0" error message is seen when you check version details. PR1584457

Interfaces and Chassis

  • Support for low power idle mode (EX4400-48T, EX4400-48P, EX4400-24T, and EX4400-24P)—Starting in Junos OS Release 21.1R1, the 1-Gbps or 100-Mpbs port switches to low power idle (LPI) mode based on the following conditions:

    • When a port operates at 1-Gbps speed and no traffic is either received or transmitted, then the port enters LPI mode. If the 1-Gbps port transfers unidirectional or bidirectional traffic, then the port will not enter LPI mode.
    • When a port operates at 100-Mbps speed, the port switches to LPI mode, based on the direction of the traffic. The show interfaces interface-name extensive command displays RX LPI when there is no RX traffic and TX LPI when there is no TX traffic.

    You can view the interface that is in LPI mode by executing the show interfaces interface-name extensive command. The output field IEEE 802.3az Energy Efficient Ethernet displays the status of the LPI mode.

    [See show interfaces extensive .]

Junos OS API and Scripting

  • On EX4400 Virtual Chassis, set system services rest http addresses statement is not supported.


  • On EX Series switches, if you are configuring a large-scale number of firewall filters on some interfaces, the FPC might crash and generate core files. PR1434927

  • "IFDE: Null uint32 set vector, ifd and IFFPC: 'IFD Ether uint32 set' (opcode 151)" error message is observed continuously in AD with base configurations. PR1485038

  • A double free vulnerability in the software forwarding interface daemon (sfid) process of Juniper Networks Junos OS allows an adjacently-connected attacker to cause a Denial of Service (DoS) by sending a crafted ARP packet to the device. Refer for more information. PR1497768

  • User while loading the kernel would see the message "GEOM: mmcsd0s.enh: corrupt or invalid GPT detected." This message has no impact to functionality and will be resolved in a future release. PR1549754

Interfaces and Chassis

  • When scale number of AE IFLs and firewall filters applied on each IFLs configured via ephemeral, followed by deactivating and activating AEs, dcd crash might be seen when deleting ephemeral instances. PR1571121


  • On EX4400 switches, error messages related to rpd process unable to connect to mplsoamd_control will be printed at every 10 seconds interval into the syslog messages. The error messages will be printed by default without any specific configurations. ex4400 rpd[15786]: %DAEMON-4-JTASK_IO_CONNECT_FAILED: MPLSOAMD I/O./var/run/mplsoamd_control: Connecting to /var/run/mplsoamd_control failed: No such file or directory PR1590719

User Interface and Configuration

  • Unsupported options can be seen under "restart" command. PR1545558

  • Python script is not supported in ZTP workflow. Python can run (during ZTP) only in few QFX Series based flex images. PR1547557