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Known Issues


This section lists the known issues in hardware and software in Junos OS Release 15.1R7 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.

Authentication and Access Control

  • On an EX4300 Virtual Chassis that is configured for 802.1X authentication, an invalid supplicant might remain in a connecting state instead of moving to a held state. PR1149008

  • EX Series switches do not send RADIUS requests after configuration of an interface-range change. This might cause some hosts to remain in a connecting state and not get authenticated. PR1326442

General Routing

  • On EX Series switches that run Enhanced Layer 2 Software (ELS), when an interface is removed from a private VLAN (PVLAN) and then added back, the corresponding MAC entry might not be deleted from the Ethernet table. PR1036265

  • In certain scenarios, EX4200 and EX4500 switches running under Junos OS Release 15.1 might have available memory as low as 19 percent. PR1306217

Layer 2 Features

  • On an EX9200-6QS line card, storm control might not work for multicast traffic. PR1191611

  • On an EX9200 switch with MC-LAG, when the enhanced-convergence statement is enabled, and when the kernel sends a next-hop message to the Packet Forwarding Engine, the full Layer 2 header is not sent and a packet might be generated with an invalid source MAC address for some VLANs. PR1223662

Network Management and Monitoring

  • SNMP polling takes more time to complete on Junos OS Release 15.1R than on Junos OS Release 12.3R. The result is an inherent CPU spike during an SNMP walk on Junos OS Release 15.1R. The problem is compounded when NMS servers send SNMP walk requests for unsupported object identifiers (OIDs). This high CPU situation can be safely avoided by configuring set snmp filter-duplicates. With this configuration enabled, duplicate SNMP requests can be filtered out and the device will only undergo one snmpd cycle for the first batch of unsupported OIDs, thus averting further CPU spikes. PR1284186

Platform and Infrastructure

  • On EX4500 switches running TACACS, you might notice the following log message: mgd[65984]: %DAEMON-5-UI_TACPLUS_ERROR: TACACS+ failure: . PR1126386

  • On EX4300 switches, packets whose size is larger than 1452 bytes will be dropped after generic routing encapsulation (GRE) because fragmentation of payload and GRE path MTU discovery are not supported on EX4300 switches. PR1293787

  • EX3300 switches running Junos OS Release 15.1R versions can randomly reboot. The issue is likely to be seen when multicast configurations are present. One of the known triggers for the issue is PIM with Dense Mode configuration. PR1284143


  • On EX4300, EX4600, and QFX5100 switches, when a VLAN is mirrored, the mirrored packets might contain 38 additional bytes. The IP address in this packet is randomly generated and might appear as one of many existing, valid IP addresses on the Internet. It might appear as ERSPAN as well, which is a proprietary non-Juniper protocol. These addresses and packet types can be ignored. They might appear as alerts in certain IDPs or IDSs and in packet analyzer applications, which you can ignore. PR1170589

  • On EX4300 10G links, preexisting MACsec sessions might not come up after the following events: (1) Process (pfex, dot1x) restart or system restart; (2) Link flaps. PR1294526

Software Installation and Upgrade

  • An invalid configuration causes EX4200, EX6200, or EX8200 switches to fail upgrading to Junos OS Release 15.1. PR1303641

  • EX3300, EX4200, EX4500, EX6200, and EX8200 switches might not have sufficient memory to validate during a software upgrade. As a workaround, run validation and software image upgrade separately. PR1333808