CLI Configuration Mode Overview
The configuration mode of the Junos OS CLI enables you to configure a device, using configuration statements to set, manage, and monitor device properties.
Understanding Junos OS CLI Configuration Mode
You can configure all Junos OS properties, including interfaces, general routing information, routing protocols, and user access, as well as several system hardware properties.
As described in Understanding the Junos OS CLI Modes, Commands, and Statement Hierarchies, a device configuration is stored as a hierarchy of statements. In configuration mode, you create a set of configuration statements to use. When you have finished entering the configuration statements and you are certain they are complete and correct, you commit them, which activates the configuration on the device.
You can create the configuration interactively or you can create an ASCII text file containing the configuration, then load it on the device and commit it.
This topic covers:
Configuration Mode Commands
The following table summarizes each CLI configuration mode command. The commands are organized alphabetically.
Table 1: Summary of Configuration Mode Commands
Remove the inactive: tag from a statement. Statements or identifiers that have been activated take effect when you next issue the commit command.
Add comments to a configuration. You can add comments only at the current hierarchy level.
Commit the set of changes to the database and cause the changes to take operational effect.
Make a copy of an existing statement in the configuration.
Add the inactive: tag to a statement, effectively commenting out the statement or identifier from the configuration. Statements or identifiers marked as inactive are ignored when you issue the commit command.
Delete a statement or identifier. All subordinate statements and identifiers contained within the specified statement path are deleted with it.
Move inside the specified statement hierarchy. If the statement does not exist, it is created.
Exit the current level of the statement hierarchy, returning to the level prior to the last edit command or exit from configuration mode. The quit and exit commands are equivalent.
Manage configurations that are contributed by SDK application packages by either displaying or deleting user-defined configuration contributed by the named SDK application package. A configuration defined in any native Junos OS package is never deleted by the extension command.
Display help about available configuration statements.
Insert an identifier into an existing hierarchy.
Load a configuration from an ASCII configuration file or from terminal input. Your current location in the configuration hierarchy is ignored when the load operation occurs.
Exit the current level of the statement hierarchy, returning to the level prior to the last edit command, or exit from configuration mode. The quit and exit commands are synonyms.
Rename an existing configuration statement or identifier.
Replace identifiers or values in a configuration.
Return to a previously committed configuration. The software saves the last 10 committed configurations, including the rollback number, date, time, and name of the user who issued the commit configuration command.
Run a CLI command without exiting from configuration mode.
Save the configuration to an ASCII file. The configuration statements up to and including the current level of the statement hierarchy are saved, along with the statement hierarchy containing it. This allows a section of the configuration to be saved, while fully specifying the statement hierarchy.
Create a statement hierarchy and set identifier values. This is similar to edit except that your current level in the hierarchy does not change.
Display the current configuration.
Display the users currently editing the configuration.
Return to the top level of configuration command mode, which is indicated by the  banner.
Move up one level in the statement hierarchy.
Update a private database.
Delete a statement or identifier. All subordinate statements and identifiers contained within the specified statement path are deleted with it. You can use regular expressions to specify a pattern. Based on this pattern, Junos OS searches for items that contain these patterns and deletes them.
Configuration Statements and Identifiers
You can configure device properties by including the corresponding statements in the configuration. Typically, a statement consists of a system-defined keyword, which is fixed text, and an optional identifier. An identifier is an identifying name that you can define, such as the name of an interface or a username, which enables you and the CLI to differentiate among a collection of statements.
Table 2: Configuration Mode Top-Level Statements
Configure the Challenge Handshake Authentication Protocol (CHAP). For information about the statements in this hierarchy, see the Junos OS Administration Library.
Configure accounting statistics data collection for interfaces and firewall filters. For information about the statements in this hierarchy, see the Network Management and Monitoring Guide.
Configure properties of the router chassis, including conditions that activate alarms and SONET/SDH framing and concatenation properties. For information about the statements in this hierarchy, see the Junos OS Administration Library.
Configure class-of-service parameters. For information about the statements in this hierarchy, see the Junos OS Class of Service User Guide for Routing Devices.
Configure filters that select packets based on their contents. For information about the statements in this hierarchy, see the Routing Policies, Firewall Filters, and Traffic Policers User Guide.
Configure forwarding options, including traffic sampling options. For information about the statements in this hierarchy, see the Junos OS Network Interfaces Library for Routing Devices.
Configure configuration groups. For information about statements in this hierarchy, see the Junos OS Administration Library.
Configure interface information, such as encapsulation, interfaces, virtual channel identifiers (VCIs), and data-link connection identifiers (DLCIs). For information about the statements in this hierarchy, see the Junos OS Network Interfaces Library for Routing Devices.
Configure routing policies, which allow you to filter and set properties in incoming and outgoing routes. For information about the statements in this hierarchy, see the Routing Policies, Firewall Filters, and Traffic Policers User Guide.
Configure routing protocols, including BGP, IS-IS, LDP, MPLS, OSPF, RIP, and RSVP. For information about the statements in this hierarchy, see the chapters that discuss how to configure the individual routing protocols in the Junos OS Routing Protocols Library and the MPLS Applications User Guide for Routing Devices.
Configure one or more routing instances. For information about the statements in this hierarchy, see the Junos OS Routing Protocols Library.
Configure protocol-independent routing options, such as static routes, autonomous system numbers, confederation members, and global tracing (debugging) operations to log. For information about the statements in this hierarchy, see the Junos OS Routing Protocols Library.
Configure IP Security (IPsec) services. For information about the statements in this hierarchy see the Junos OS Administration Library.
Configure SNMP community strings, interfaces, traps, and notifications. For information about the statements in this hierarchy, see the Network Management and Monitoring Guide.
Configure systemwide properties, including the hostname, domain name, Domain Name System (DNS) server, user logins and permissions, mappings between hostnames and addresses, and software processes. For information about the statements in this hierarchy, see the Junos OS Administration Library.
Configuration Statement Hierarchy
The Junos OS configuration consists of a hierarchy of statements. There are two types of statements:
Container statements, which are branches that can contain other statements (including additional container statements or leaf statements). Container statements at the top of the hierarchy are considered to be the trunk of the hierarchy tree.
Leaf statements (contained by container statements) which do not contain other statements
The container and leaf statements form the configuration hierarchy. Each statement at the top level of the configuration hierarchy resides at the trunk of a hierarchy tree. These top-level statements are container statements, containing other statements that form the tree branches. The leaf statements are the leaves of the hierarchy tree. An individual hierarchy of statements, which starts at the trunk of the hierarchy tree, is called a statement path.
The following illustration shows the hierarchy tree, illustrating a statement path for the part of the protocol configuration hierarchy responsible for configuring the hello-interval statement on an interface in an OSPF area.
The protocols statement is a top-level statement at the trunk of the configuration tree. The ospf, area, and interface statements are all subordinate container statements of a higher statement (they are branches of the hierarchy tree). The hello-interval statement is a leaf on the tree, which in this case contains a data value, namely the length of the hello-interval, in seconds.
The following configuration example illustrates the statement hierarchy as shown in Figure 1:
[edit protocols ospf area area-number interface interface-name]
The command displays the configuration as follows:
The CLI indents each level in the hierarchy to indicate each statement’s relative position in the hierarchy. Additionally, in general, it sets off each level with braces, using an open brace at the beginning of each hierarchy level and a closing brace at the end. If the statement at a hierarchy level is empty, the braces are not printed.
Each leaf statement ends with a semicolon. If the hierarchy does not extend as far as a leaf statement, the last statement in the hierarchy ends with a semicolon.
The configuration hierarchy can also contain “oneliners” at the lowest level in the hierarchy. Oneliners remove one level of braces in the syntax and display the container statement, its identifiers, the child or leaf statement and its attributes all on one line.
For example, dynamic-profile dynamic-profile-name aggregate-clients; is a oneliner because the dynamic-profile statement, its identifier dynamic-profile-name, and leaf statement aggregate-clients all appear on one line when you run the show command in the configuration mode:
Entering and Exiting the Junos OS CLI Configuration Mode
You configure Junos OS by entering configuration mode and creating a hierarchy of configuration mode statements.
To enter configuration mode, use the configure command.
When you enter configuration mode, the following configuration mode commands are available:
entering configuration mode
possible completions: <[Enter]> Execute this command activate Remove the inactive tag from a statement annotate Annotate the statement with a comment commit Commit current set of changes copy Copy a statement deactivate Add the inactive tag to a statement delete Delete a data element edit Edit a sub-element exit Exit from this level help Provide help information insert Insert a new ordered data element load Load configuration from ASCII file quit Quit from this level rename Rename a statement replace Replace character string in configuration rollback Roll back to previous committed configuration run Run an operational-mode command save Save configuration to ASCII file set Set a parameter show Show a parameter status Show users currently editing configuration top Exit to top level of configuration up Exit one level of configuration wildcard Wildcard operations  user@host>
When making configuration changes, if you exit configuration mode without committing them, the intended changes will be lost.
You must have configure permission to view and use the configure command. When in configuration mode, you can view and modify only those statements for which you have access privileges.
If you enter configuration mode and another user is also in configuration mode, a message shows the user’s name and the part of the configuration the other user is viewing or editing:
user@host> configure Entering configuration mode Users currently editing the configuration: root terminal d0 (pid 4137) on since 2008-04-09 23:03:07 PDT, idle 7w6d 08:22  The configuration has been changed but not committed  user@host#
Up to 32 users can be in configuration mode simultaneously, and they all can make changes to the configuration at the same time.
To exit configuration mode, use the exit configuration-mode configuration mode command from any level, or use the exit command from the top level. For example:[edit protocols ospf area 0.0.0.0 interface so-0/0/0]user@host# exit configuration-modeexiting configuration modeuser@host>user@host# exitexiting configuration modeuser@host>
If you try to exit from configuration mode using the exit command and the configuration contains changes that have not been committed, you see a message and prompt:user@host# exitThe configuration has been changed but not committedExit with uncommitted changes? [yes,no] yesExiting configuration modeuser@host>
To exit with uncommitted changes without having to respond to a prompt, use the exit configuration-mode command. This command is useful when you are using scripts to perform remote configuration.user@host# exit configuration-modeThe configuration has been changed but not committedExiting configuration modeuser@host>
Issuing Relative Junos OS Configuration Mode Commands
The top or up command followed by another configuration command—such as edit, insert, delete, deactivate, annotate, or show—enables you to quickly move to the top of the hierarchy or to a level above the area you are configuring.
To issue configuration mode commands from the top of the hierarchy, use the top command and specify a configuration command. For example:
To issue configuration mode commands from a location higher up in the hierarchy, use the up configuration mode command; specify the number of levels you want to move up the hierarchy and then specify a configuration command. For example:
Using Command Completion in Configuration Mode
This topic shows you how to access command help and to use basic command completion in the Junos OS CLI configuration mode. In each case, it is the use of the question mark (?) character, either by itself or in combination with a partial command or configuration statement.
To list the configuration mode commands, use the ? command by itself:
<[Enter]> Execute this command activate Remove the inactive tag from a statement annotate Annotate the statement with a comment commit Commit current set of changes copy Copy a statement deactivate Add the inactive tag to a statement delete Delete a data element edit Edit a sub-element exit Exit from this level extension Extension operations help Provide help information insert Insert a new ordered data element load Load configuration from ASCII file quit Quit from this level rename Rename a statement replace Replace character string in configuration rollback Roll back to previous committed configuration run Run an operational-mode command save Save configuration to ASCII file set Set a parameter show Show a parameter status Show users currently editing configuration top Exit to top level of configuration up Exit one level of configuration wildcard Wildcard operations user@host#
To list all the statements available at a particular hierarchy level, use ? after the name of the hierarchy level you wish to view. In this example, we are viewing the edit and edit protocols hierarchies.
user@host# edit ?
Possible completions: > accounting-options Accounting data configuration > chassis Chassis configuration > class-of-service Class-of-service configuration > firewall Define a firewall configuration > forwarding-options Configure options to control packet sampling > groups Configuration groups > interfaces Interface configuration > policy-options Routing policy option configuration > protocols Routing protocol configuration > routing-instances Routing instance configuration > routing-options Protocol-independent routing option configuration > snmp Simple Network Management Protocol > system System parameters
user@host# edit protocols ?
Possible completions: <[Enter]> Execute this command > bgp BGP options > connections Circuit cross-connect configuration > dvmrp DVMRP options > igmp IGMP options > isis IS-IS options > ldp LDP options > mpls Multiprotocol Label Switching options > msdp MSDP options > ospf OSPF configuration > pim PIM options > rip RIP options > router-discovery ICMP router discovery options > rsvp RSVP options > sapSession Advertisement Protocol options > vrrp VRRP options | Pipe through a command
To list all commands that start with a particular string or letter, enter the string and/or letter and end with the ? character. Here is a list of all the routing-options commands starting with the letter “a.”
user@host# edit routing-options a?
Possible completions: > aggregate Coalesced routes > autonomous-system Autonomous system number
This is a list of all configured Asynchronous Transfer Mode (ATM) interfaces, using just a partial completion (at?):
user@host# edit interfaces at?
<interface_name> Interface name at-0/2/0 Interface name at-0/2/1 Interface name 
You can also show a list of all configured policy statements:
user@host# show policy-options policy-statement ?
user@host# show policy-options policy-statement <policy_name> Name to identify a policy filter lo0only-v4 Name to identify a policy filter lo0only-v6 Name to identify a policy filter lo2bgp Name to identify a policy filter
Notational Conventions Used in Junos OS Configuration Hierarchies
When you are working in Junos OS command-line interface (CLI) configuration mode, the banner on the line preceding the prompt indicates the current hierarchy level. In the following example, the level is [edit protocols ospf]:
(Junos OS documentation uses user@host# as the standard configuration mode prompt. In an actual CLI session, the prompt shows your user ID and the configured name of the Juniper Networks device you are working on.)
Use the set ? command to display the statements that you can include in the configuration at the current level. The help apropos command is also context-sensitive, displaying matching statements only at the current command hierarchy level and below.
Statements are listed alphabetically within each hierarchy and subhierarchy. If a subhierarchy is sufficiently long that it might be difficult to determine where it ends and its next peer statement begins, the subhierarchy appears at the end of its parent hierarchy instead of in alphabetical order. In this case, a placeholder appears in its actual alphabetical position.
For example, at the [edit interfaces interface-name unit logical-unit-number] hierarchy level, the family family-name subhierarchy has more than 20 child statements, including several subhierarchies with child statements of their own. The full family family-name hierarchy appears at the end of its parent hierarchy ([edit interfaces interface-name unit logical-unit-number]), and the following placeholder appears at its actual alphabetical position:
Another exception to alphabetical order is that the disable statement always appears first in any hierarchy that includes it.