Useful Cisco Commands for Network Administration (IOS and NX-OS)
As a network engineer, working with Cisco devices requires familiarity with both IOS and NX-OS commands. This guide covers essential commands that every network administrator should know when managing Cisco devices. When implementing the configurations, please verify which platform you are using as some commands may vary between IOS and NX-OS.
Show Clock
Checking the system time is fundamental for troubleshooting and log correlation:
switch# show clock
10:50:34.146 CET Tue Feb 18 2025
Time source is NTP
Show Running Configuration for Clock Manager
To view the clock manager configuration:
switch# show run clock_manager
!Command: show running-config clock_manager
!Running configuration last done at: Tue Feb 18 10:46:12 2025
!Time: Tue Feb 18 10:48:59 2025
Set NTP Server
Proper time synchronization is crucial for network operations. Configure NTP with:
switch(config)# ntp server <ip> vrf use-vrf <default/management>
Show Environment
Monitor hardware health including temperature sensors:
switch# show environment
...
Temperature:
--------------------------------------------------------------------
Module Sensor MajorThresh MinorThres CurTemp Status
(Celsius) (Celsius) (Celsius)
--------------------------------------------------------------------
A Sensor1 XX XX XX OK
A Sensor2 XX XX XX OK
A Sensor3 XX XX XX OK
A Sensor4 XX XX XX OK
Show Archive
Configuration archival is important for change management and recovery:
switch# show archive
The maximum archive configurations allowed is 10.
The archiving time-period is 1439 minutes.
The next archive will be in 1221 minutes.
Write-mem mode is enabled.
There are currently 2 archive configurations saved.
The next archive file will be named sftp://user:pass@[IPv6:address]/backup/device-xyz-confg-<timestamp>-2
Archive # Name
1 sftp://user:pass@[IPv6:address]/export/home/user/backup/device-xyz-confg-<date-time>-0
2 sftp://user:pass@[IPv6:address]/export/home/user/backup/device-xyz-confg-<date-time>-1 <- Most Recent
3
License Smart Transport
Disable Smart Licensing transport when offline management is required:
switch(config)# license smart transport off
This command prevents the device from communicating with the Cisco Smart Software Manager.
Show SNMP OID Statistics Last Access
Monitor SNMP activity for troubleshooting purposes:
switch# show snmp oid-statistics last-access
- SNMP Latest OID Stats
Object ID Last Access TS Last Access Last-polled NMS Rsp Time
The output displays the last access time for the specified OID, helping with SNMP monitoring verification.
Show Interface Hardware Mappings
View hardware mapping information for interfaces:
switch# show interface hardware-mappings
...
Slice - Slice Number. N/A for BCM systems
...
---------------------------
Name Ifindex Smod Unit HPort FPort NPort VPort Slice SPort SrcId MacId MacSP VIF Block BlkSrcID
---------------------------
Eth1/1 1a000000 1 0 108 255 0 -1 1 36 72 27 0 1 1 0
Eth1/2 1a000200 1 0 112 255 4 -1 1 40 80 28 0 5 1 8
Show Interface Status
Monitor operational status of all interfaces including speed, duplex, and VLAN assignment:
switch# show interface status
Port Name Status Vlan Duplex Speed Type
--------------------------------------------------------------------------------
Eth1/1 Uplink-Core connected routed full 1000 1000base-T
Eth1/2 To-Distribution connected 10 full 1000 1000base-T
Eth1/3 -- disabled 1 full 1000 1000base-T
Show IP Route
Display the IP routing table to verify network paths and routing protocol information:
switch# show ip route
IP Route Table for VRF "default"
'*' denotes best ucast next-hop
'**' indicates shared leak-vrf routes
'x' indicates backup next-hop
'%' indicates exclusive path
'+' indicates recursive entry
'&' indicates external path
'*' 10.0.0.0/24, ubest/mbest: 1/0
*via 10.1.1.2, Eth1/1, [110/20], 01:15:22, ospf-1, intra
'*' 10.0.1.0/24, ubest/mbest: 1/0
*via 192.168.1.1, Eth1/2, [110/30], 00:45:12, ospf-1, intra
Show VLAN
List all configured VLANs with their IDs, names, and associated ports:
switch# show vlan
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Eth1/3, Eth1/4, Eth1/5
10 Production active Eth1/2, Eth1/6, Eth1/7
20 Development active Eth1/8, Eth1/9
30 Guest active Eth1/10, Eth1/11
100 Management active Eth1/12
VLAN Type Vlan-mode
---- ----- ----------
1 enet CE
10 enet CE
20 enet CE
30 enet CE
100 enet CE
Show Processes CPU
Monitor CPU utilization by processes to identify performance bottlenecks:
switch# show processes cpu | head
CPU utilization for five seconds: 2%/0%; one minute: 3%; five minutes: 1%
PID Runtime(ms) Invoked uSecs Process
------ ----------- -------- ------- --------
1 1234567 123456 10000 init
2 234567 23456 10000 kmigratord
3 3456789 345678 10000 ksoftirqd/0
4 4567890 456789 10000 kworker/0:0
5 567890 56789 10000 kswapd0
Show Logging
Display recent system logs for troubleshooting and monitoring events:
switch# show logging | tail
2025 Feb 18 10:30:15.123456 switch %ETHPORT-5-IF_DOWN: Interface Ethernet1/1 is down
2025 Feb 18 10:30:16.234567 switch %ETHPORT-5-IF_UP: Interface Ethernet1/1 is up
2025 Feb 18 10:32:22.345678 switch %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet1/2, changed state to Down
2025 Feb 18 10:32:23.456789 switch %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet1/2, changed state to Up
2025 Feb 18 10:35:44.567890 switch %PLATFORM-2-MOD_DETECT: Module 1 detected (Serial number ABC1234D567)
Show Module
Display information about installed modules/line cards including status and hardware details:
switch# show module
Mod Ports Module-Type Model Status
--- ----- ------------------------------------- ---------------------- ----------
1 48 1000 Mbps Optical SFP on 48 GE PoE+ N9K-C9396PX active *
2 48 1000 Mbps Optical SFP on 48 GE N9K-C9396PX active *
3 32 10 Gigabit Ethernet N9K-C93180YC-FX active *
4 32 10 Gigabit Ethernet N9K-C93180YC-FX active *
Mod Sw Hw World-Wide-Name(s) (WWN)
--- -------------- ------ --------------------------------------------------
1 9.3(10) 1.1 NA
2 9.3(10) 1.1 NA
3 9.3(10) 1.0 NA
4 9.3(10) 1.0 NA
Show MAC Address Table
Display learned MAC addresses and their associated interfaces and VLANs:
switch# show mac address-table
Legend:
* - primary entry, G - Gateway MAC, (R) - Routed MAC, O - Overlay MAC
age - seconds since last seen,+ - primary entry using vPC peer-gateway MAC
VLAN MAC Address Type age Secure NTFY Ports/SWID.SSID.LID
--------+----------------+--------+---------+------+----+------------------
* 1 0011.2233.4455 dynamic 0 F F Po10
* 10 aabb.ccdd.eeff dynamic 300 F F Eth1/2
* 10 0012.3456.7890 dynamic 120 F F Eth1/6
* 20 aaaa.bbbb.cccc dynamic 450 F F Eth1/8