show module
Displays the status, model, serial numbers, and hardware/software versions of all modules installed in a modular Cisco switch or router, used for verifying hardware inventory and module health.
Definition: show module is a Cisco IOS privileged exec command. Displays the status, model, serial numbers, and hardware/software versions of all modules installed in a modular Cisco switch or router, used for verifying hardware inventory and module health.
Overview
The 'show module' command is a critical diagnostic tool for network engineers managing modular Cisco switches and routers. It provides a detailed inventory of all line cards, supervisor modules, power supplies, and other field-replaceable units (FRUs) installed in the chassis. This command is essential for verifying hardware compatibility, tracking serial numbers for asset management, and diagnosing module-level failures.
Unlike 'show inventory' which focuses on device identifiers, 'show module' offers real-time operational status (e.g., 'ok', 'faulty', 'power-deny') and uptime for each module. It is the go-to command when a module fails to come online, when adding or replacing hardware, or when troubleshooting intermittent connectivity issues that may stem from a faulty line card. The command outputs buffered text that can be lengthy on large chassis; use 'terminal length 0' to avoid pagination.
Privilege level 15 (enable) is required. It does not affect the running configuration. Understanding module status helps isolate problems to specific hardware, reducing mean time to repair (MTTR).
For example, a 'power-deny' status indicates insufficient power budget, while 'faulty' suggests hardware failure. The command also displays software version per module, which is vital when running mixed IOS versions during upgrades. In a broader workflow, 'show module' is often the first step before 'show logging' or 'debug' to confirm hardware health.
It is also used during initial deployment to verify that all ordered modules are recognized. For CCNP candidates, mastering this command is key for campus network troubleshooting and maintenance.
show moduleWhen to Use This Command
- Verify that all line cards in a chassis are online and operational after a reboot.
- Check the serial numbers and part numbers of modules for RMA or inventory tracking.
- Identify mismatched firmware versions across modules in a switch stack.
- Troubleshoot a module that is not powering up or is in a faulty state.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| all | all | Displays detailed information for all modules, including those that are not online or have failed. Without this keyword, only operational modules are shown. Common mistake: forgetting 'all' when troubleshooting a missing module. |
| slot | <slot-number> | Specifies a particular slot number to display information for a single module. Valid values depend on chassis (e.g., 1-9 for Catalyst 6500). Useful for focusing on a specific module without scrolling through all output. |
Command Examples
Basic module status check on a Catalyst 3850 stack
show moduleMod Ports Module-Type Model Status --- ----- ----------------------------------- ------------------ ---------- 1 48 48-port 10/100/1000 PoE+ WS-C3850-48P ok 2 48 48-port 10/100/1000 PoE+ WS-C3850-48P ok 3 48 48-port 10/100/1000 PoE+ WS-C3850-48P ok Mod MAC-Address(es) Serial-Num --- --------------------------------------- ---------- 1 70ca.9b12.3400 to 70ca.9b12.342f FOC12345678 2 70ca.9b12.3500 to 70ca.9b12.352f FOC87654321 3 70ca.9b12.3600 to 70ca.9b12.362f FOC11223344 Mod Hw Fw Sw --- ------ ------------ ----------- 1 V01 16.12.03 16.12.03 2 V01 16.12.03 16.12.03 3 V01 16.12.03 16.12.03
The first table shows each module (stack member) with port count, module type, model, and status (ok means operational). The second table lists MAC address ranges and serial numbers for each module. The third table shows hardware revision (Hw), firmware version (Fw), and software version (Sw). All modules show identical firmware and software, which is ideal.
Checking a faulty module in a Catalyst 4500 chassis
show moduleMod Ports Card Type Model Serial No. --- ----- -------------------------------------- ------------------ ----------- 1 48 48-port 10/100/1000 (RJ45) WS-X4548-GB-RJ45 SAL1234ABCD 2 48 48-port 10/100/1000 (RJ45) WS-X4548-GB-RJ45 SAL5678EFGH 3 48 48-port 10/100/1000 (RJ45) WS-X4548-GB-RJ45 SAL9012IJKL Mod MAC-Address(es) Hw Fw Sw Status --- --------------------------------------- ------ ------------ ------------ ---------- 1 0011.2233.4400 to 0011.2233.442f 1.0 12.2(54)SG 12.2(54)SG ok 2 0011.2233.4500 to 0011.2233.452f 1.0 12.2(54)SG 12.2(54)SG faulty 3 0011.2233.4600 to 0011.2233.462f 1.0 12.2(54)SG 12.2(54)SG ok
Module 2 shows status 'faulty', indicating a hardware problem. The serial number and MAC range are still displayed, but the module is not operational. This output helps identify which line card needs replacement.
Understanding the Output
The 'show module' output typically contains multiple tables. The first table lists each module (or stack member) with its port count, module type, model, and status. Status values include: 'ok' (normal), 'faulty' (hardware failure), 'power-deny' (insufficient power), 'offline' (administratively down), or 'unknown'.
The second table shows MAC address ranges (useful for identifying module connectivity) and serial numbers (for inventory/RMA). The third table (or combined) shows hardware revision, firmware version, and software version. In a stack, each switch is a module.
Key things to watch: all modules should show 'ok'; firmware and software versions should match across modules to avoid compatibility issues; serial numbers help track individual units. If a module shows 'faulty' or 'power-deny', investigate power budget or hardware failure.
Configuration Scenarios
Verify new line card installation on a Catalyst 4500 switch
After installing a new 48-port line card in slot 3, the network engineer needs to confirm the switch recognizes it and the card is operational.
Topology
Switch1 (WS-C4510R+E) with Supervisor in slot 1, existing line cards in slots 2 and 4, new card in slot 3.Steps
- 1.Step 1: Power on the switch and wait for boot to complete.
- 2.Step 2: Enter privileged EXEC mode: Switch> enable
- 3.Step 3: Verify module status: Switch# show module
- 4.Step 4: Check that slot 3 shows 'ok' status and correct model (e.g., WS-X4748-RJ45V+E).
- 5.Step 5: If status is 'other' or 'faulty', reseat the card or check power budget.
! No configuration required; verification only. Switch# show module
Verify: Expected output snippet: Mod Ports Card Type Model Serial No. Status --- ----- -------------------------------------- ------------------ ----------- ------ 1 2 Supervisor Engine V-10GE (Active) WS-X4516-10GE JAE1234567 ok 2 48 10/100/1000BaseT (RJ45) WS-X4748-RJ45V+E JAE2345678 ok 3 48 10/100/1000BaseT (RJ45) WS-X4748-RJ45V+E JAE3456789 ok 4 24 1000BaseX (SFP) WS-X4724-SFP JAE4567890 ok
Watch out: If the new card shows 'power-deny', the chassis power supply may be undersized. Check 'show power' to confirm available power.
Troubleshoot a faulty supervisor module on a Catalyst 6500
A Catalyst 6509 switch has lost connectivity; the standby supervisor is not taking over. The engineer needs to check module status to identify the fault.
Topology
Cat6509 with dual supervisors (slots 5 and 6), line cards in slots 1-4. Active supervisor in slot 5, standby in slot 6.Steps
- 1.Step 1: Connect to console and enter enable mode: Switch> enable
- 2.Step 2: Run 'show module all' to see all modules including failed ones.
- 3.Step 3: Look at slot 6 status; if 'faulty', note the serial number for RMA.
- 4.Step 4: Check uptime: if standby shows '00:00:00', it may have just rebooted.
- 5.Step 5: Use 'show logging' to correlate any crash messages.
! No configuration needed. Switch# show module all
Verify: Expected output snippet: Mod Ports Card Type Model Serial No. Status --- ----- -------------------------------------- ------------------ ----------- ------ 5 2 Supervisor Engine 720 (Active) WS-SUP720-3B JAE5678901 ok 6 2 Supervisor Engine 720 (Standby) WS-SUP720-3B JAE6789012 faulty ...
Watch out: A 'faulty' supervisor may still pass traffic but cannot take over. Always check both supervisors' status. If the standby is 'other', it may be in a different software version.
Troubleshooting with This Command
When troubleshooting hardware issues, 'show module' is your first line of defense. A healthy module displays 'ok' status. Problem indicators include 'faulty', 'power-deny', 'other', or 'unknown'.
'Faulty' typically means hardware failure; check 'show logging' for error messages like 'SP: The system has experienced a serious fault'. 'Power-deny' indicates insufficient power; verify with 'show power' and consider upgrading power supplies. 'Other' often means the module is booting or in a transitional state; wait a few minutes and recheck.
'Unknown' may indicate a mismatch in hardware or software compatibility. Focus on the 'Status' and 'Model' fields. If a module shows 'ok' but ports are down, the issue may be cabling or configuration, not the module itself.
A step-by-step diagnostic flow: 1) Run 'show module all' to see all modules. 2) Identify any non-ok status. 3) For 'faulty', note the serial number and initiate RMA. 4) For 'power-deny', run 'show power' and calculate total draw. 5) For 'other', wait and recheck; if persistent, reseat the module. 6) If a module is missing entirely, check physical seating and 'show inventory' to see if the switch detects it at all. Correlate with 'show logging' for hardware errors, and 'show environment' for temperature or voltage alarms. In a high-availability setup, also check 'show redundancy' to ensure supervisor failover is configured correctly.
Remember that 'show module' does not show port-level errors; use 'show interfaces' for that. For CCNP-level troubleshooting, combine 'show module' with 'show diagnostic' for online diagnostics and 'show platform' for deeper hardware insight.
CCNA Exam Tips
CCNA exam may ask which command verifies module status in a stack; 'show module' is the answer.
Remember that 'show module' is used on modular switches (e.g., 3850 stack, 4500 chassis) not on fixed-configuration switches.
The exam might present output with a 'faulty' module and ask what action to take (replace the module).
Know that 'show module' also displays MAC address ranges, which can be used to identify which module a device is connected to.
Common Mistakes
Using 'show module' on a fixed switch (e.g., 2960) expecting output; it will show nothing or an error.
Confusing 'show module' with 'show inventory' which shows detailed hardware IDs but not status.
Assuming 'ok' status means the module is fully functional; it only means the module is powered and detected, not that all ports are up.
show module vs show inventory
Both 'show module' and 'show inventory' are used to inspect hardware components on Cisco devices, but they are often confused due to overlapping information. 'show module' focuses on module status and versioning for modular chassis, while 'show inventory' provides a comprehensive hardware listing including product IDs and serial numbers across all components.
| Aspect | show module | show inventory |
|---|---|---|
| Detail Level | Provides status (online/offline), software version, and hardware version per module | Lists PID, VID, and serial number for each hardware component |
| Scope | Limited to modules (line cards, supervisors) in modular chassis | Covers all field-replaceable units: chassis, modules, power supplies, fans |
| Output Format | Tabular display with per-module rows and columns for status, version, etc. | List format with component description and identifiers |
| Hardware Identification | Less emphasis on unique identifiers; omits serial numbers for many components | Essential for inventory management and warranty lookup |
| Typical Use Case | Verifying module operational state and software compatibility | Auditing hardware assets and verifying correct hardware install |
Use show module when you need to check the operational status and software version of modules in a modular switch or router.
Use show inventory when you need a complete hardware inventory with product IDs and serial numbers for asset management.
Platform Notes
In IOS-XE (e.g., Catalyst 9300/9400), the command syntax is identical: 'show module'. However, on some IOS-XE platforms like Catalyst 3850, the output may include 'Switch' and 'Stack' information. On NX-OS (e.g., Nexus 9000), the equivalent command is 'show module' as well, but the output format differs: it includes 'Mod', 'Ports', 'Module-Type', 'Model', 'Status'.
NX-OS also supports 'show module internal' for deeper diagnostics. On ASA firewalls, there is no direct equivalent; use 'show inventory' or 'show module' on ASA 5585-X with SSP modules. In IOS-XR (e.g., ASR 9000), the command is 'show platform' which provides similar module-level information.
For IOS versions: 12.x and 15.x have similar output; 16.x (IOS-XE) may add 'Redundancy' columns. On Catalyst 6500 running IOS 12.2(33)SXJ, 'show module' includes 'Sw' (software version) column. Always use 'show module all' to see failed modules; without 'all', only operational modules appear.
On some platforms, 'show module' may be replaced by 'show hardware' or 'show inventory' for asset tracking. Be aware that on virtual switches (e.g., VSS), 'show module' shows both chassis modules. For accurate serial numbers, use 'show module' over 'show inventory' as it provides real-time status.
Related Commands
show environment
Displays the environmental status of the device, including temperature, voltage, and fan status, to monitor hardware health and detect potential failures.
show inventory
Displays hardware inventory including chassis, modules, power supplies, and fan trays with their product IDs (PIDs), version IDs (VIDs), and serial numbers.
show version
Displays system hardware and software information, including IOS version, uptime, memory, interfaces, and configuration register, used to verify device identity and software compatibility.
Practice for the CCNA 200-301
Test your knowledge with practice questions covering all CCNA 200-301 exam domains.
Practice CCNA 200-301 Questions