First Use

By default, the devices support login through both the serial console and SSH (Secure Shell).

When initially logging into the device, you will need to use the console port (referred to as the serial port below) to establish a connection. After configuring the management interface’s IP address, you can then use SSH to log into the device. Local login via the serial console is the fundamental method for accessing the device, and it forms the basis for configuring other login methods. The specific steps are as follows:

Connect the Lines

This series of devices utilize RJ-45 connectors for serial console connections. The distribution of serial console ports varies among different models. Generally, they can be found on the front panel of the device, while some might be located on the rear panel, often marked with the label “CON.”

After the device is powered on, connect the device’s serial console port to a server or PC. It’s important to ensure that the communication parameter settings of the user terminal match the default configuration of the device’s serial console to establish communication. The default values for each parameter are as shown in the table below:

Parameter	Default Value
Baud Rate	115200
Data Bits	8
Stop Bits	1
Parity	None

Serial Port Login Device

1.Initial Login via Console Port:

Connect to the device through the Console port. After pressing Enter, a login prompt will appear.

Welcome to minicom 2.7
OPTIONS: I18n
Compiled on Nov 15 2018, 20:18:47.
Port /dev/ttyUSB1, 11:24:17
Press CTRL-A Z for help on special keys

Debian GNU/Linux 9 sonic ttyS0
sonic login:

2.Logging into the Device with Default Credentials:

Username: admin

Password: asteros

Last login: Fri Mar 14 03:10:51 2025 from 192.168.51.235
...Entering cli view, please wait...
sonic#

3.Configuring the Management Interface IP Address(Any port, with in band management):

sonic# configure
sonic(config)# interface ethernet 1
sonic(config-if-1)# ip address 30.1.1.2/24 30.1.1.1

4.Saving the Configuration:

sonic# write
save running-config...
Existing files will be overwritten, continue? [y/N]: y
Running command: /usr/local/bin/sonic-cfggen -d --print-data > /etc/sonic/config_db.json

Getting Familiar with Using CISCO-LIKE Command Line

How to Enter the Command Line View

Operation	Command	Description
Enter the CLI view	sonic cli	By default, upon logging into the device, you will automatically enter the command line view.
Exit the CLI view	system bash	Use the ‘exit’ command to return to the command line configuration interface.

Common Keywords

Keywords	Description
no	Cancel or disable a specific setting
show this	Display the current configuration of the current view
configure terminal	Enter the system configuration mode
delete	Delete a configuration file
reboot	Reboot the device
write	Save the current configuration
shutdown	Disable or turn off a port
exit	Exit to the previous level or log out

Command Line Usage Assistance

When entering an incomplete keyword, pressing the Tab or Space key will automatically complete the keyword.

If you encounter issues while using the command line, you can utilize the help function to get assistance, eliminating the need to memorize extensive and intricate commands.

While entering a command, pressing the Tab key will display a list of matching keywords. Entering ”?” will provide hints for relevant keywords or explanations of parameters.

sonic(config)#
aaa acl anti-attack-check arp authentication
clock copp counters crm crm-resource
dhcp dot1x feature hash history
image interface ipfix ipv4-source-check ipv6-source-check
l2-multicast-table license link-aggregation lldp local-user
mac-address mac-flapping mac-learning mac-limit mclag
mirror monitor-link nat nd ndp
ntp platform port-isolate-group portal ptp
qos queue ra raguard running-config
savi sla snmp-agent snooping stp
sub-interface supported-timezones synce syslog-storage-capacity system
tacacs traffic-behavior user-bind version vlan
vrf vxlan ztp isis bfd
route-map-unused debugging ip bgp mpls
ipv6 evpn router-id logging nexthop-group
pathd vrrp

sonic# configure terminal
sonic(config)# access-list l3 test ingress <tab>
<cr>
sonic(config)# access-list l3 test <enter>
Syntax error: The command is not completed
sonic(config)# access-list l3 test1 ingress
sonic(config-l3-acl-test1)# ?
end Exit to the exec Mode
exit Exit from current mode
no Negate a command or set its defaults
rule Add an access list entry
show show running-config

sonic(config-l3-acl-test1)# rule ?
rule ID (0..500)

sonic(config-l3-acl-test1)# rule 1 ?
source-mac Specify source mac address
destination-mac Specify destination mac address
ethernet-type Specify ethernet protocol type
outer-vlan Specify outer VLAN id
vlan-pri Specify outer VLAN priority

Configuration File Management

The configuration files for this series of devices are in JSON (JavaScript Object Notation) format. JSON is a lightweight data interchange format, and its file extension is typically .json.

Viewing Configuration File

By default, the system configuration files are stored in the /etc/sonic directory. The default system configuration file is named config_db.json. When performing configuration saving or restoration operations, it’s this file that gets modified, determining the initial configuration upon the device’s next startup. Additionally, this directory also contains backups of configuration files, labeled with timestamps, which facilitates configuration recovery for users. Every time the “write” command is executed, a new config_db.json file is generated to save the current configuration, and the original file’s name is modified to the format config_bd+timestamp.

Configuration Saving

After a user logs into the device, configurations made through command-line operations or other means are temporary. If you require persistent configurations, you should manually save the modified settings. This involves updating the current configuration to the default configuration file, config_db.json. If you don’t save the configurations, the device’s settings will revert to their state before modifications after a reboot.

Operation	Command	Description
Save configuration	write