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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 14.2R8 for the EX Series.

Dynamic Host Configuration Protocol

  • DHCP clients can send packets without Option 255 (EX9200)—On EX Series switches, starting with Junos OS Release 14.2R2, you can override the default configuration of the DHCP local server and enable clients to send DHCP packets that do not include Option 255 (end-of-options). The default behavior in Junos OS is to drop packets that do not include Option 255. To override that default behavior, configure the allow-no-end-options CLI statement under the [system services dhcp-local-server overrides] hierarchy level.
  • Format change for DHCP Option 18—On EX9200 switches with DHCP snooping configured, when the VLAN ID is appended to the prefix of DHCP option 18, it appears in decimal format instead of hexadecimal format.

Interfaces and Chassis

  • Configuration statement to correct mismatches between MAC and ARP entries in MC-LAGs (EX9200)—Starting with Junos OS Release 13.2R4 but first documented in Release 14.2R6, the arp-l2-validate configuration statement is available as a workaround when network issues or conditions result in MAC and ARP entries going out of sync in an MC-LAG scenario. Configure the arp-l2-validate statement at the [edit interfaces irb] hierarchy level to recognize and correct mismatches between MAC and ARP entries related to the next-hop interface. You can remove the arp-l2-validate configuration when the network issues or conditions are resolved.


  • Support for status deprecated statement in YANG modules (EX Series)—Starting in Junos OS Release 14.2R8, Juniper Networks YANG modules include the status deprecated statement to indicate configuration statements, commands, and options that are deprecated.

Network Management and Monitoring

  • New system log message indicating the difference in the Packet Forwarding Engine counter value (EX9200)—Effective in Junos OS Release 14.2R2, if the counter value of a Packet Forwarding Engine is reported to be less than its previous value, then the residual counter value is added to the newly reported value only for that specific counter. In that case, the CLI shows the MIB2D_COUNTER_DECREASING system log message for that specific counter.

Port Security

  • Enhanced output for show ethernet-switching interface extensive CLI command—Starting with Junos OS Release 14.2, the output of the show ethernet-switching interface extensive CLI command includes the fields VLAN members, TAG, and STP state. The Logical interface flags field now includes STCL, which indicates that the port is disabled because storm control is in effect, and MMAS, which indicates that the port is disabled because the MAC address move limit has been exceeded.

User Interface and Configuration

  • Changed destination file format for transfer-on-commit feature (EX9200)—Starting with Junos OS Release 14.2, the format of the destination filename for the transfer-on-commit feature is changed from router-name_juniper.conf.n.gz_YYYYMMDD_HHMMSS to router-name_YYYYMMDD_HHMMSS_juniper.conf.n.gz.

Modified: 2017-12-12