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Known Limitations

Learn about known limitations in Junos OS Release 21.4R3 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

  • 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

  • Once vxlan is configured on an IFD, its always treated as vlxan port even though L2 vlan exists.PR1570689

  • On EX4300-MP platforms, when the command 'request system software rollback' is performed device is going down and dcpfe cores are dumping.PR1631640

  • Unified ISSU on QFX5120-48Y and EX4650 switches will not be supported if there is a change in the Cancun versions of the chipset SDKs between the releases. This is a product limitation as change in the Cancun firmware leads to the chip reset and hence ISSU is impacted. The Cancun versions in the chipset SDKs should be the same between two JUNOS OS releases for ISSU to work. PR1634695


  • While upgrading the image from 21.2T to 21.3DCB, the no-validate knob is mandatory for the upgrade command to proceed. PR1586481

Platform and Infrastructure

  • USB image upgrade for RE-1800x4 K2re "bare-metal" platforms (SRX5k, MX240, MX480, MX960, MX2010, EX9208 chassis) might not be successful. PR1630040