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Essential Commands for Cisco Small Business, SG & Catalyst 1300 Switches

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Supported Switch Models

  • Model: Cisco SG550X
  • Model: Cisco SG350X
  • Model: Cisco CBS250
  • Model: Cisco Catalyst 1300

Commands

Show Commands

  • Display the firmware version:
Cisco# show version
  • Display the serial number:
Cisco# show system id
  • Display the model, uptime, hostname, and MAC address:
Cisco# show system unit 1
  • Display the MAC address table:
Cisco# show mac address-table
  • Display GBIC (SFP module) information:
Cisco# show inventory
  • Display recent log messages:
Cisco# show logging
  • Display learned IP addresses (ARP table):
Cisco# show arp

User Account Management

  • Change the password of an existing user:
Cisco(config)# username cisco password myNEWpassword
  • Create an admin user with privilege level 15:
Cisco(config)# username cisco privilege 15 password myNEWpassword
  • Disable the password maximum lifetime:
Switch(config)# password aging 0

Miscellaneous

  • Change the hostname of the switch:
Cisco(config)# hostname Switch
  • Save the current running configuration to startup config:
Switch# copy running-config startup-config
Switch# write
  • Set a static IP address on VLAN 1 interface:
Switch(config)# interface vlan1
Switch(config-if)# ip address 192.168.1.100 255.255.255.0
Switch(config-if)# no ip address dhcp
  • Configure the DNS server address:
Switch(config)# ip name-server 192.168.1.110
  • Disable DNS lookup for unknown commands (prevents delays if you mistype commands):
Switch(config)# no ip domain lookup
  • Set the default gateway:
Switch(config)# interface vlan1
Switch(config-if)# ip default-gateway 192.168.1.254
  • Reboot the switch:
Switch# reload
  • Configure a range of interfaces (use gi1, gi2, etc. for CBS models):
Switch(config)# interface range ge1/0/4,ge1/0/30
Switch(config)# interface range ge1/0/4-18
  • Enable the SSH server:
Switch(config)# ip ssh server
  • Disable the HTTP server (for web UI access):
Switch(config)# no ip http server
  • Disable the Bonjour discovery protocol:
Switch(config)# no bonjour enable
  • Disable PnP (Plug and Play) auto-discovery:
Switch(config)# no pnp enable
  • Check the switch’s CPU usage:
Switch# show cpu utilization
  • Globally disable Auto Smartport (automatic interface configuration, CBS series only):
Switch(config)# no macro auto
  • Erase configuration and perform a factory reset:
Switch(config)# delete startup-config
  • Disable logging of system messages to the console:
Switch(config)# no logging console

Import / Export Configuration

  • Export the current configuration to a TFTP server:
Switch# copy run tftp://tftp_server/YYYY-MM-DD
  • Import a configuration file from a TFTP server:
Switch# copy tftp://tftp_server/YYYY-MM-DD run

Update Firmware

Easy Method (Direct Boot from TFTP)

  • Boot directly from the new firmware image on a TFTP server:
Switch# boot system tftp://tftp_server/firmware.bin
  • Reboot the switch to apply the firmware:
Switch# reload

Normal Method (Copy to Flash Memory)

  • Copy the firmware image to the switch’s flash memory:
Switch# copy tftp://tftp_server/firmware.bin flash://system/images/
  • List available firmware versions stored in flash:
Switch# show bootvar
  • Select the new firmware image to boot from:
Switch# boot system image-2
  • Reboot the switch:
Switch# reload

LACP (Link Aggregation)

Diagram of two Cisco switches connected via LACP using a Port-Channel with interfaces Gi1/0/1 and Gi1/0/2.

Switch01

  • Create a Port-Channel using interfaces Gi1/0/1 and Gi1/0/2:
Switch01(config)# interface range gi1/0/1-2
Switch01(config-if-range)# channel-group 1 mode auto
  • Configure the Port-Channel interface as a trunk:
Switch01(config)# interface Port-Channel 1
Switch01(config-if)# switchport mode trunk
Switch01(config-if)# switchport trunk allowed vlan all

Switch02

  • Repeat the same configuration on Switch02:
Switch02(config)# interface range gi1/0/1-2
Switch02(config-if-range)# channel-group 1 mode auto
Switch02(config)# interface Port-Channel 1
Switch02(config-if)# switchport mode trunk
Switch02(config-if)# switchport trunk allowed vlan all

Show

  • Verify LACP status and port-channel details:
Switch01# show lacp port-channel 1
Switch01# show lacp gi1/0/1

PoE (Power over Ethernet)

  • Turn off PoE on interface Gi1/0/1:
Switch(config)# interface gi1/0/1
Switch(config-if)# no power inline
  • Turn on PoE on interface Gi1/0/1:
Switch(config)# interface gi1/0/1
Switch(config-if)# power inline auto
  • Display global PoE status and per-port consumption:
Switch# show power inline
Switch# show power inline gi1/0/1

VLAN Configuration

  • Create VLAN 4 and assign it a name:
Switch(config)# vlan database
Switch(config-vlan)# vlan 4
Switch(config)# interface vlan 4
Switch(config-if)# name VoIP
  • Assign VLAN 4 to an access port (e.g., Gi1/0/24):
Switch(config)# interface GigabitEthernet 1/24
Switch(config-if)# switchport mode access
Switch(config-if)# switchport access vlan 4
  • Configure trunk mode and allowed VLANs on Te1/0/1:
Switch(config)# interface te 1/0/1
Switch(config-if)# switchport mode trunk
Switch(config-if)# switchport trunk allowed vlan none
Switch(config-if)# switchport trunk allowed vlan add 4,100,101,150

Locked Port / Disable Port Security

Message: Your port has port security enabled and has noticed that the MAC address on that port is different from what the port had originally learned.

  • Reactivate the interface Gi2/0/4 if it is in a shutdown or error-disabled state:
Switch# set interface active gi2/0/4
  • Check the current port security status:
Switch# show ports security gi2/0/4
  • Disable port security on the interface:
Switch(config) # interface gi2/0/4
Switch(config-if)# no port security

sFlow

  • Set up an sFlow receiver (replace <index> and <IP address>):
Switch(config)# sflow receiver <index of the receiver> <sflow receiver ip> port 2055
  • Enable sFlow sampling on multiple interfaces:
Switch(config)# interface range GigabitEthernet1/0/1-48
Switch(config-if-range)# sflow flow-sampling 1024 1
Switch(config-if-range)# sflow counters-sampling 600 1
  • Turn off sFlow on a specific interface (e.g. Te1/0/1):
Switch(config)# interface TengigabitEthernet1/0/1
Switch(config-if)# no sflow counters-sampling
Switch(config-if)# no sflow flow-sampling

Port Mirroring / SPAN

  • Set interface Gi1/0/1 as the SPAN destination (e.g., connected to a packet analyzer):
Switch(config)# monitor session 1 destination interface GigabitEthernet1/0/1
  • Mirror all traffic (both directions) from interfaces Gi1/0/2 and Gi1/0/3:
Switch(config)# monitor session 1 source interface GigabitEthernet1/0/2 both
Switch(config)# monitor session 1 source interface GigabitEthernet1/0/3 both

NTP (Network Time Protocol)

  • Show the current system clock:
Switch# show clock
  • Check SNTP (Simple NTP) status and sync info:
Switch# show sntp status
  • Enable SNTP and set the NTP server (replace with actual server):
Switch(config)# clock source sntp
Switch(config)# sntp unicast client enable
Switch(config)# sntp server 0.pool.ntp.org

Spanning Tree Protocol (STP)

  • Show the current STP configuration and status:
Switch# show spanning-tree
  • Set the STP priority to make this switch the root bridge:
Switch(config)# spanning-tree priority 4096
  • Activate Rapid Spanning Tree Protocol (RSTP):
Switch(config)# spanning-tree mode rstp

Configure Stack

Stack two SG switches

Note: To stack two Cisco switches, ensure they use the same model and firmware version. Connect them via Te1/0/1 and Te1/0/2.

Two switches connected using TenGigabitEthernet stacking ports.

Switch01

  • Enter Stack Unit 1 configuration context:
Switch01(config)# stack unit 1
  • Set Unit ID to 1 and define stacking links:
Switch01(unit)# stack configuration links te1-2 unit-id 1
  • Save and reboot:
Switch01(unit)# do write
Switch01(unit)# do reload

Switch02

  • Enter Stack Unit 1 configuration context:
Switch02(config)# stack unit 1
  • Set Unit ID to 2 and define stacking links:
Switch02(unit)# stack configuration links te1-2 unit-id 2
  • Save and reboot:
Switch02(unit)# do write
Switch02(unit)# do reload

Verification Commands

  • Show stack configuration:
Stack# show stack configuration

Unit Id  After Reboot Configuration
         Unit Id   Stack Links   
-------- ------- --------------- 
1        1       te1-2           
2        2       te1-2
  • Display general stack information:
Stack# show stack

Topology is Chain
Units stack mode: Native

Unit Id     MAC Address        Role    Network Uplink 
                                       Port    Port   
                                       Type    Type   
------- ------------------- ---------- ------- ------ 
   1     40:a6:e8:e6:9c:11    active     gi      te   
   2     40:a6:e8:e6:9c:12   standby     gi      te
  • Show stack link details:
Stack# show stack links details

Topology is Chain

UNIT ID   Link     Status   Speed Neighbor Neighbor     Neighbor
                                  Unit ID  Link         MAC Address
------- -------- ---------- ----- -------- -------- -------------------
   1      te1      Active    10G     2       te2     40:a6:e8:e6:9c:12
   1      te2      Active    10G     2       te1     40:a6:e8:e6:9c:12
   2      te1      Active    10G     1       te2     40:a6:e8:e6:9c:11
   2      te2      Active    10G     1       te1     40:a6:e8:e6:9c:11

Remove Stack Configuration

  • Remove stacking configuration from a unit:
Switch01(config)# stack unit 1
Switch01(unit)# no stack configuration