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System Settings

Specifying the Physical Location of the Switch

To specify the physical location of the switch, specify the following options for the location statement at the [edit system] hierarchy level:

  • altitude feet—Number of feet above sea level.

  • building name—Name of the building, 1 to 28 characters in length. If the string contains spaces, enclose it in quotation marks (" ").

  • country-code code—Two-letter country code.

  • floor number—Floor in the building.

  • hcoord horizontal-coordinate—Bellcore Horizontal Coordinate.

  • lata service-area—Long-distance service area.

  • latitude degrees—Latitude in degree format.

  • longitude degrees—Longitude in degree format.

  • npa-nxx number—First six digits of the phone number (area code and exchange).

  • postal-code postal-code—Postal code.

  • rack number—Rack number.

  • vcoord vertical-coordinate—Bellcore Vertical Coordinate.

The following example shows how to specify the physical location of the switch:

Modifying the Default Time Zone for a Router or Switch Running Junos OS

The default local time zone on the router or switch is UTC (Coordinated Universal Time, formerly known as Greenwich Mean Time, or GMT).

  • To modify the local time zone, include the time-zone statement at the [edit system] hierarchy level:

You can use the GMT hour-offset option to set the time zone relative to UTC (GMT) time. By default, hour-offset is 0. You can configure this to be a value from –14 to +12.

You can also specify the time-zone value as a string such as PDT (Pacific Daylight Time) or WET (Western European Time), or specify the continent and major city.


Junos OS complies with the POSIX time-zone standard, which is counter-intuitive to the way time zones are generally indicated relative to UTC. A time zone ahead of UTC (east of the Greenwich meridian) is commonly indicated as GMT +n; for example, the Central European Time (CET) zone is indicated as GMT +1. However, this is not true for POSIX time zone designations. POSIX indicates CET as GMT-1. If you include the set system time-zone GMT+1 statement for a router in the CET zone, your router time will be set to one hour behind GMT, or two hours behind the actual CET time. For this reason, you might find it easier to use the POSIX time-zone strings, which you can list by entering set system time-zone ?.

For the time zone change to take effect for all processes running on the router or switch, you must reboot the router or switch.

The following example shows how to change the current time zone to America/New_York:

Configuring Junos OS to Extend the Default Port Address Range

By default, the upper range of a port address is 5000. You can increase the range from which the port number can be selected to decrease the probability that someone can determine your port number.

  • To configure Junos OS to extend the default port address range, include the source-port statement at the [edit system internet-options] hierarchy level:

upper-limit upper-limit is the upper limit of a source port address and can be a value from 5000 through 65,355.

Configuring Junos OS to Select a Fixed Source Address for Locally Generated TCP/IP Packets

By default, the source address included in locally generated Transmission Control Protocol/IP (TCP/IP) packets, such as FTP traffic, and in User Datagram Protocol (UDP) and IP packets, such as Network Time Protocol (NTP) requests, is chosen as the local address for the interface on which the traffic is transmitted. This means that the local address chosen for packets to a particular destination might change from connection to connection based on the interface that the routing protocol has chosen to reach the destination when the connection is established. If multiple equal-cost next hops are present for a destination, locally generated packets use the lo0 address as a source.

  • To configure the software to select a fixed address to use as the source for locally generated IP packets, include the default-address-selection statement at the [edit system] hierarchy level:

If you include the default-address-selection statement in the configuration, the Junos OS chooses the system default address as the source for most locally generated IP packets. The default address is usually an address configured on the lo0 loopback interface. For example, if you specified that SSH and telnet use a particular address, but you also have default-address selection configured, the system default address is used.

Rebooting and Halting a Device

To reboot the switch, issue the request system reboot command.

  • Not all options shown in the preceding command output are available on all devices. See the documentation for the request system reboot command for details about options.

  • When you issue the request system reboot hypervisor command on QFX10000 switches, the reboot takes longer than a standard Junos OS reboot.

Similarly, to halt the switch, issue the request system halt command.


Before entering this command, you must have access to the switch’s console port in order to bring up the Routing Engine.


When you issue this command on an individual component in a QFabric system, you will receive a warning that says “Hardware-based members will halt, Virtual Junos Routing Engines will reboot.” If you want to halt only one member, use the member option. You cannot issue this command from the QFabric CLI.

Issuing the request system halt command on the switch halts the Routing Engine. To reboot a Routing Engine that has been halted, you must connect through the console.