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Configuring Junos OS on the EX9253

EX9253 Switch Default Configuration

Each EX9253 switch is programmed with a factory default configuration that contains the values set for each configuration parameter when a switch is shipped. The default configuration file sets values for system parameters such as the system log and file messages.

When you commit changes to the configuration, a new configuration file is created that becomes the active configuration. You can always revert to the factory default configuration (see Reverting to the Default Factory Configuration for the EX Series Switch).

This topic shows the factory default configuration file of an EX9253 switch:

Connecting and Configuring an EX9253 Switch

Before you begin to connect and configure the switch, gather the following information:

  • Name the switch will use on the network

  • Domain name the switch will use

  • IP address and prefix length information for the Ethernet interface

  • IP address of a default switch

  • IP address of a DNS server

  • Password for the root user

The EX9253 switch is shipped with the Junos OS preinstalled and ready to be configured when the switch is powered on. There are two 16-MB internal NAND Flash memory devices located on the baseboard for BIOS storage. You can insert the USB storage device into the USB slot on the front panel. The switch also has two built-in M.2-based solid-state drives (SSDs) (labeled SSD0 and SSD1). There are three copies of the software: one each on the SSD drives and one on a USB flash drive that can be inserted into the slot in the faceplate of the Routing Engine.

When the switch boots, it first attempts to start the image on the USB flash drive. If there is no USB flash drive installed or if the attempt otherwise fails, the switch next attempts to start the software from the SSD drive installed in slot SSD0, and finally from the SSD drive installed in slot SSD1.

You configure the switch by issuing Junos OS command-line interface (CLI) commands, either on a console device attached to the console (CON) port on the front panel, or over a telnet connection to a network connected to the Ethernet management (MGMT) port on the front panel.

This procedure connects the switch to the network, but does not enable it to forward traffic. For complete information about enabling the switch to forward traffic, including examples, see the Junos OS configuration guides.

To perform initial configuration:

  1. Log in as the root user. There is no password.
  2. Start the CLI.
  3. Enter the configuration mode.
  4. Configure the name of the switch. If the name includes spaces, enclose the name in double quotation marks (“ ”).
  5. Configure the switch’s domain name.
  6. Configure the IP address and prefix length for the switch’s management Ethernet interface.
  7. Configure the IP address of a backup router, which is used only when the routing protocol is not running.
  8. Configure the IP address of a Domain Name System (DNS) server.
  9. Set the root authentication password by entering either a plain-text password, an encrypted password, or an SSH public key string (DSA or RSA).




  10. (Optional) Configure the static routes to remote subnets with access to the management port. Access to the management port is limited to the local subnet. To access the management port from a remote subnet, you must add a static route to that subnet within the routing table.
  11. Configure the Telnet service.
  12. (Optional) Display the configuration to verify that it is correct.
  13. (Optional) Configure additional properties by adding the necessary configuration statements.
  14. Commit the configuration to activate it on the switch.
  15. Exit the configuration mode.

Ensure that the removable storage media that contains a copy of Junos OS is not installed in the switch except when you want to install Junos OS from the storage media. If the storage media is installed during normal operation and if the switch is rebooted intentionally or accidentally (for example, as a result of a power outage), the configuration in the switch is deleted and the copy of the software in the storage media is installed in the switch.