In which configuration mode is show ip interface brief used?

The show ip interface brief command is entered in Privileged EXEC mode on Cisco IOS devices.

DiagnosticsPrivileged EXEC

show ip interface brief

Instantly check which interfaces are up, which are shutdown, and what IP addresses are assigned.

Definition: show ip interface brief is a Cisco IOS privileged exec command. Displays a one-line summary of all interfaces showing the IP address assigned, operational status (up/down), and line protocol status. The fastest way to get a device health overview.

Overview

The 'show ip interface brief' command is one of the most frequently used commands in Cisco IOS for quickly assessing the operational state of all IP interfaces on a device. It provides a concise, tabular summary of each interface's IP address, status (line protocol), and protocol state (IP connectivity). This command is essential for network engineers during initial device bring-up, routine health checks, and troubleshooting connectivity issues.

The underlying concept is the OSI model's Layer 1 (physical) and Layer 2 (data link) status, combined with Layer 3 (IP) configuration. The 'Status' column reflects the line protocol state (up/down), indicating whether the physical layer and data link layer are operational. The 'Protocol' column indicates whether IP is enabled and functioning on that interface (up/down).

When both are 'up', the interface is fully operational for IP traffic. Engineers reach for this command as a first step in troubleshooting because it quickly reveals whether an interface is administratively down, has a cable fault, or has an IP configuration issue. Alternatives like 'show interfaces' provide more detailed statistics but are more verbose.

'show ip interface' gives detailed IP-specific information but is not as quick for a broad overview. In a typical workflow, after configuring interfaces, an engineer runs 'show ip interface brief' to verify that all intended interfaces are up and have the correct IP addresses. During troubleshooting, if a user reports no connectivity, the engineer checks this command to see if the relevant interface is down.

If the interface is down, they investigate physical issues; if up but protocol down, they check Layer 2 issues like VLAN mismatches or encapsulation. The command is available in privileged EXEC mode (enable) and does not require any special privilege level beyond 15. It does not affect the running configuration and is safe to run at any time.

Output is buffered and may be truncated in some terminal sessions; using 'terminal length 0' before the command can prevent paging. This command is supported across all Cisco IOS platforms, including routers and switches, and is a staple for CCNA and CCNP candidates.

Syntax·Privileged EXEC

show ip interface brief

When to Use This Command

First troubleshooting command — quick view of all interface states on a device
Verify IP addresses are assigned correctly after configuration
Identify shutdown interfaces (administratively down)
Confirm router interfaces are up before troubleshooting routing protocols

Command Examples

Typical output on a router

Router# show ip interface brief
Interface              IP-Address      OK? Method Status                Protocol
GigabitEthernet0/0    192.168.1.1     YES NVRAM  up                    up
GigabitEthernet0/1    10.0.0.1        YES NVRAM  up                    up
GigabitEthernet0/2    unassigned      YES unset  administratively down down
Loopback0             1.1.1.1         YES NVRAM  up                    up

Understanding the Output

Status = Layer 1 (physical): up = cable/link signal present, administratively down = shutdown command applied, down = no signal. Protocol = Layer 2: up = keepalives passing, down = keepalives failing or Layer 1 down. Method: NVRAM = IP loaded from saved config, manual = set during current session, unset = no IP.

OK? YES/NO = IP address configuration validity.

Configuration Scenarios

Verify interface configuration after initial setup of a new router

A network engineer has just configured IP addresses on GigabitEthernet0/0 and GigabitEthernet0/1 of a new Cisco router and needs to confirm that the interfaces are up and have the correct IPs before connecting to the rest of the network.

Topology

R1(Gi0/0)---10.0.12.0/30---(Gi0/0)R2
R1(Gi0/1)---192.168.1.0/24---PC1

Steps

1.Step 1: Enter privileged EXEC mode: Router> enable
2.Step 2: Run the command: Router# show ip interface brief
3.Step 3: Examine the output to verify that both GigabitEthernet0/0 and GigabitEthernet0/1 show 'up' in both the Status and Protocol columns.
4.Step 4: Confirm the IP addresses match the intended configuration (e.g., 10.0.12.1 and 192.168.1.1).

Configuration

! Full IOS config block
Router(config)# interface GigabitEthernet0/0
Router(config-if)# ip address 10.0.12.1 255.255.255.252
Router(config-if)# no shutdown
Router(config-if)# exit
Router(config)# interface GigabitEthernet0/1
Router(config-if)# ip address 192.168.1.1 255.255.255.0
Router(config-if)# no shutdown

Verify: Command: show ip interface brief Expected output: Interface IP-Address OK? Method Status Protocol GigabitEthernet0/0 10.0.12.1 YES manual up up GigabitEthernet0/1 192.168.1.1 YES manual up up

Watch out: A common mistake is forgetting to issue the 'no shutdown' command on the interface, causing the Status to show 'administratively down'.

Troubleshoot a down interface on a switch

A user on VLAN 10 cannot reach the default gateway. The network engineer suspects the switch interface connected to the router is down and uses 'show ip interface brief' to quickly check the status of the SVI for VLAN 10.

Topology

SW1(Vlan10)---192.168.10.0/24---PC1
SW1(Gi0/1)---trunk---R1(Gi0/0)

Steps

1.Step 1: Enter privileged EXEC mode: Switch> enable
2.Step 2: Run the command: Switch# show ip interface brief
3.Step 3: Look for the Vlan10 interface. If Status is 'down' or 'administratively down', proceed to check the physical ports and VLAN configuration.
4.Step 4: If Vlan10 is down, check if any access ports in VLAN 10 are up and if the SVI has 'no shutdown' applied.

Configuration

! Full IOS config block
Switch(config)# interface Vlan10
Switch(config-if)# ip address 192.168.10.1 255.255.255.0
Switch(config-if)# no shutdown
Switch(config-if)# exit
Switch(config)# interface GigabitEthernet0/1
Switch(config-if)# switchport mode trunk
Switch(config-if)# no shutdown

Verify: Command: show ip interface brief Expected output (healthy): Interface IP-Address OK? Method Status Protocol Vlan10 192.168.10.1 YES manual up up GigabitEthernet0/1 unassigned YES unset up up If Vlan10 shows 'down' in Status, the SVI is not operational.

Watch out: A common mistake is forgetting that an SVI requires at least one switchport in the VLAN to be in an up/up state for the SVI to come up. If all ports in VLAN 10 are down, the SVI will remain down.

Troubleshooting with This Command

When troubleshooting network connectivity issues, 'show ip interface brief' is often the first command a network engineer runs. A healthy interface displays 'up' in both the Status and Protocol columns. If the Status is 'administratively down', the interface has been disabled with the 'shutdown' command.

If Status is 'down', there is a physical layer problem such as a bad cable, disconnected cable, or faulty transceiver. If Status is 'up' but Protocol is 'down', the issue is at Layer 2, such as a mismatched encapsulation (e.g., HDLC vs PPP on serial links), a VLAN mismatch on a trunk, or a spanning-tree blocking state. For Ethernet interfaces, a common scenario is the Status showing 'up' but Protocol showing 'down' due to a port security violation or errdisable state.

The engineer should focus on the specific interface that is relevant to the problem. For example, if a host on VLAN 10 cannot reach the gateway, check the SVI for VLAN 10. If the SVI is down, check the physical ports in that VLAN.

The command also helps identify misconfigured IP addresses; if an interface has an unexpected IP address or shows 'unassigned', the configuration needs correction. A step-by-step diagnostic flow: 1) Run 'show ip interface brief' to get an overview. 2) Identify any interfaces that are not up/up. 3) For interfaces with Status 'administratively down', use 'no shutdown' to enable them. 4) For Status 'down', check cables, SFPs, and the remote device. 5) For Protocol 'down', check Layer 2 configurations (trunk allowed VLANs, native VLAN, encapsulation). 6) Correlate with 'show interfaces' for detailed error counters (CRC, collisions, input errors) and 'show logging' for interface state changes. For example, if a serial interface shows 'up/down', 'show interfaces serial 0/0/0' might reveal a clocking mismatch or keepalive failure.

The command is also useful for verifying that loopback interfaces are up, as they are often used for management or routing protocol stability. In summary, 'show ip interface brief' provides a quick snapshot that guides further troubleshooting steps.

CCNA Exam Tips

CCNA exam must-know: status/protocol combinations — up/up (working), up/down (Layer 1 OK but L2 failing — encapsulation mismatch), down/down (no physical signal), admin down/down (shut command applied)

Use no shutdown to bring up administratively down interfaces

This is the most common first troubleshooting command on any CCNA lab

Common Mistakes

Not using this as the FIRST troubleshooting step when a connection fails

Forgetting that Cisco router interfaces are shutdown by default (unlike switches)

Confusing down/down (physical) with administratively down/down (manual shutdown)

Not checking both ends of a link — one end up, other end down indicates a cable or shutdown issue

show ip interface brief vs show interfaces

These two commands are often confused because both display interface information, but they serve distinct purposes: show ip interface brief provides a quick summary of IP address and status, while show interfaces offers comprehensive Layer 1/2 details.

Aspect	show ip interface brief	show interfaces
Output format	One-line per interface; compact table	Multi-line per interface; verbose text block
Information depth	IP address, interface status, protocol status only	MAC, MTU, bandwidth, duplex, speed, counters, queues, etc.
Typical use case	Quick health check or inventory of interfaces	Troubleshooting link issues, performance, or errors
Time to run	Very fast; minimal output	Slower; large output on devices with many interfaces
IP address display	Shows IP address (if configured) unassigned	Does not show IP address unless combined with other commands
Layer coverage	Primarily Layer 3 (IP) with Layer 1/2 status summary	Layer 1 (physical), Layer 2 (protocol, MAC, errors)

Use show ip interface brief when you need a quick snapshot of which interfaces are up/down and their IP addresses.

Use show interfaces when troubleshooting performance issues or checking detailed statistics like errors, duplex mismatches, or queue drops.

Platform Notes

In IOS-XE (e.g., Catalyst 9000 switches), the command syntax and output are identical to classic IOS. However, on some IOS-XE platforms, the output may include additional interface types like 'GigabitEthernet' or 'TwentyFiveGigE'. The command is also available in NX-OS, but the equivalent is 'show ip interface brief' as well, though the output format may differ slightly (e.g., column headers).

On Cisco ASA firewalls, the equivalent command is 'show interface ip brief' or 'show ip address' depending on the version. In ASA 9.x, 'show interface ip brief' provides a similar summary. For IOS-XR, the command is 'show ip interface brief' but the output is more detailed and may require specifying a VRF.

For example, in IOS-XR, 'show ip interface brief' shows all interfaces, but to see a specific VRF, use 'show ip interface brief vrf <name>'. There are no significant differences between IOS 12.x, 15.x, and 16.x for this command; the output remains consistent. However, in newer versions, the 'Method' column may show 'DHCP' if the address was obtained via DHCP.

On some platforms, the 'OK?' column may be omitted. Always ensure you are in privileged EXEC mode (enable) to run the command. On devices with many interfaces, the output may be long; use 'terminal length 0' to disable paging.

The command does not require any additional license or feature set and is available in the IP Base image.

Related Commands

show cdp neighbors

Displays information about directly connected Cisco devices discovered via CDP (Cisco Discovery Protocol) including device IDs, local and remote interfaces, holdtime, device capabilities, and platform model.

show interfaces

Displays detailed Layer 1 and Layer 2 statistics for all interfaces or a specific interface: line protocol state, hardware type, MAC address, MTU, bandwidth, duplex, speed, input/output rates, error counters, and queue statistics.

show ip route

Displays the IP routing table showing all known routes, their source protocols, administrative distances, metrics, next-hops, and outgoing interfaces.

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