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.
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.
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.
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.
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 the hardware inventory of the device, including serial numbers and part numbers for all installed modules, used for asset management and verifying hardware components.
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.
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