System.md

title	JNCIS Notes System
permalink	/JNCIS_Notes/System/

• Misc
• Login
• Service
• Syslog
• Chassis

Misc

no-panic-on-nmi: no kernel crash at RE memory error default-address-selection: use lo0 as source address for locally generated packets dump-on-panic: create a core file when system crash backup-router: When the router is booting, the routing protocol process (rpd) is not running; therefore, the router has no static or default routes. To allow the router to boot and to ensure that the router is reachable over the network if the routing protocol process fails to start properly, you configure a backup router (running IP version 4 [IPv4] or IP version 6 [IPv6]), which is a router that is directly connected to the local router (that is, on the same subnet).

Login

allow-commands: specify the (additional) operational mode commands that members of a login class can use (than whatever current class permits). deny-commands: specify the operational mode commands that the user is denied permission to issue, even though the permissions set with the permissions statement would allow it. Permission table:

Permission Flag	Description
access	Can view the access configuration in configuration mode using the show configuration operational mode command.
access-control	Can view and configure access information at the [edit access] hierarchy level.
admin	Can view user account information in configuration mode and with the show configuration command.
admin-control	Can view user accounts and configure them at the [edit system login] hierarchy level.
all	Has all permissions.
clear	Can clear (delete) information learned from the network that is stored in various network databases using the clear commands.
configure	Can enter configuration mode using the configure command.
control	Can perform all control-level operations—all operations configured with the -control permission flags.
field	Reserved for field (debugging) support.
firewall	Can view the firewall filter configuration in configuration mode.
firewall-control	Can view and configure firewall filter information at the [edit firewall] hierarchy level.
floppy	Can read from and write to the removable media.
flow-tap	Can view the flow-tap configuration in configuration mode.
flow-tap control	Can view the flow-tap configuration in configuration mode and can configure flow-tap configuration information at the [edit services flow-tap] hierarchy level.
flow-tap-operation	Can make flow-tap requests to the router. For example, a Dynamic Tasking Control Protocol (DTCP) client must authenticate itself to JUNOS as an administrative user. That account must have flow-tap-operation permission. '''Note: '''flow-tap operation is not included in the all permission.
interface	Can view the interface configuration in configuration mode and with the show configuration operational mode command.
interface-control	Can view the interface configuration in configuration mode and with the show configuration operational mode command.
maintenance	Can perform system maintenance, including starting a local shell on the router and becoming the superuser in the shell using the su root command, and can halt and reboot the router using the request system commands.
network	Can access the network by entering the ping, SSH, telnet, and traceroute commands.
reset	Can restart software processes using the restart command and can configure whether software processes are enabled or disabled at the [edit system processes] hierarchy level.
rollback	Can use the rollback command to return to a previously committed configuration other than the most recently committed one.
routing	Can view general routing, routing protocol, and routing policy configuration information in configuration and operational modes.
routing-control	Can view general routing, routing protocol, and routing policy configuration information and configure general routing at the [edit routing-options] hierarchy level, routing protocols at the [edit protocols] hierarchy level, and routing policy at the [edit policy-options] hierarchy level.
secret	Can view passwords and other authentication keys in the configuration.
secret-control	Can view passwords and other authentication keys in the configuration and can modify them in configuration mode.
security	Can view security configuration in configuration mode and with the show configuration operational mode command.
security-control	Can view and configure security information at the [edit security] hierarchy level.
shell	Can start a local shell on the router by entering the start shell command.
snmp	Can view Simple Network Management Protocol (SNMP) configuration information in configuration and operational modes.
snmp-control	Can view SNMP configuration information and modify SNMP configuration at the [edit snmp] hierarchy level.
system	Can view system-level information in configuration and operational modes.
system-control	Can view system-level configuration information and configure it at the [edit system] hierarchy level.
trace	Can view trace file settings in configuration and operational modes.
trace-control	Can view trace file settings and configure trace file properties.
view	Can use various commands to display current systemwide, routing table, and protocol-specific values and statistics. Cannot view secret configuration.

Service

connection-limit: limit—Maximum number of simultaneous connections (a value from 1 through 250). The default is 75. rate-limit: limit—Maximum number of connection attempts accepted per minute (a value from 1 through 250). The default is 150.

Syslog

System Logging Facilities:

Facility	Type of Event or Error
any	All (messages from all facilities)
authorization	Authentication and authorization attempts
change-log	Changes to the JUNOS configuration
conflict-log	Specified configuration is invalid on the routing platform type
daemon	Actions performed or errors encountered by system processes
dfc	Events related to dynamic flow capture
firewall	Packet filtering actions performed by a firewall filter
ftp	Actions performed or errors encountered by the FTP process
interactive-commands	Commands issued at the JUNOS command-line interface (CLI) prompt or by a client application such as a JUNOScript or NETCONF client
kernel	Actions performed or errors encountered by the JUNOS kernel
pfe	Actions performed or errors encountered by the Packet Forwarding Engine
user	Actions performed or errors encountered by user-space processes

System Log Message Severity Levels: Messages from the facility that are rated at that level or higher are logged to the destination.

Severity Level	Description
any	Includes all severity levels
none	Disables logging of the associated facility to a destination
emergency	System panic or other condition that causes the routing platform to stop functioning
alert	Conditions that require immediate correction, such as a corrupted system database
critical	Critical conditions, such as hard drive errors
error	Error conditions that generally have less serious consequences than errors in the emergency, alert, and critical levels
warning	Conditions that warrant monitoring
notice	Conditions that are not errors but might warrant special handling
info	Events or nonerror conditions of interest

Chassis

no-source-route: Discard IP traffic that has loose or strict source-route constraints. Use this option when you want the router to use only the IP destination address on transit traffic for forwarding decisions.