show ipv4 interface brief
Displays a summary of all IPv4 interfaces on the router, including their status, protocol, and IP address.
Overview
The 'show ipv4 interface brief' command is a fundamental tool for any network engineer working with Cisco IOS-XR. It provides a concise, one-line summary of every IPv4-enabled interface on the router, displaying the interface name, assigned IP address (or 'unassigned'), administrative status, and line protocol status. This command is essential for quickly assessing the overall health of the router's interfaces, especially after configuration changes, reloads, or during troubleshooting. The concept behind the command is to give a high-level view without the verbosity of the full 'show interfaces' output. In Cisco IOS-XR, the command follows the same syntax as classic IOS but uses the XR interface naming convention (e.g., GigabitEthernet0/0/0/0). It fits into troubleshooting workflows as a first step: checking if interfaces are up/up and have the correct IP addresses. If an interface shows 'Shutdown/Down', it is administratively disabled; if 'Up/Down', there is a Layer 1 or Layer 2 issue; if 'Down/Down', the physical connection is likely faulty. The command is also useful for verifying that all expected interfaces are present and operational after a router reboot or hardware replacement.
show ipv4 interface brief [type interface-path-id]When to Use This Command
- Quickly verify the operational status of all IPv4 interfaces after a reload or configuration change.
- Identify interfaces that are administratively down or have no IP address assigned.
- Troubleshoot connectivity issues by checking if an interface is up/up and has the correct IP address.
- Monitor interface status during network maintenance or troubleshooting sessions.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| type interface-path-id | [type interface-path-id] | Optional parameter to specify a particular interface. The type is the interface type (e.g., GigabitEthernet, Loopback) and interface-path-id is the rack/slot/module/port notation. If omitted, all IPv4 interfaces are displayed. |
Command Examples
Basic show ipv4 interface brief
show ipv4 interface briefInterface IP-Address Status Protocol GigabitEthernet0/0/0/0 192.168.1.1 Up Up GigabitEthernet0/0/0/1 10.10.10.1 Up Up GigabitEthernet0/0/0/2 unassigned Shutdown Down Loopback0 1.1.1.1 Up Up MgmtEth0/0/CPU0/0 172.16.1.1 Up Up
The output shows each interface, its IP address (or 'unassigned'), administrative status (Status), and line protocol status (Protocol). 'Up/Up' means the interface is operational. 'Shutdown/Down' indicates the interface is administratively disabled.
Show specific interface
show ipv4 interface brief GigabitEthernet0/0/0/0Interface IP-Address Status Protocol GigabitEthernet0/0/0/0 192.168.1.1 Up Up
Filters the output to show only the specified interface. Useful for quickly checking a single interface without scrolling through all interfaces.
Understanding the Output
The output of 'show ipv4 interface brief' consists of four columns: Interface, IP-Address, Status, and Protocol. The Interface column lists the interface name in the format Type/rack/slot/module/port. The IP-Address column shows the primary IPv4 address assigned to the interface, or 'unassigned' if none is configured. The Status column indicates the administrative state: 'Up' means the interface is enabled, 'Shutdown' means it is administratively down, and 'Down' means it is operationally down (e.g., no cable). The Protocol column shows the line protocol state: 'Up' indicates that the protocol is running (e.g., carrier detected), while 'Down' indicates a problem such as no carrier or keepalive failure. A healthy interface shows 'Up' in both Status and Protocol. Common problem indicators include 'Shutdown/Down' (administratively disabled), 'Up/Down' (physical layer up but protocol down, often due to Layer 1 or Layer 2 issues), or 'Down/Down' (physical layer problem).
Configuration Scenarios
Verifying Interface Status After Configuration
After configuring a new interface with an IP address, you want to ensure it is up and operational.
Topology
N/ASteps
- 1.Configure the interface with an IP address and no shutdown.
- 2.Use 'show ipv4 interface brief' to verify the interface appears with the correct IP and status Up/Up.
! Configuration interface GigabitEthernet0/0/0/3 ipv4 address 192.168.2.1 255.255.255.0 no shutdown !
Verify: Run 'show ipv4 interface brief GigabitEthernet0/0/0/3' and confirm output shows IP-Address 192.168.2.1, Status Up, Protocol Up.
Watch out: If the interface remains 'Shutdown/Down', ensure you issued 'no shutdown'. If 'Up/Down', check the physical cable and remote end.
Troubleshooting with This Command
When troubleshooting connectivity issues on Cisco IOS-XR, 'show ipv4 interface brief' is often the first command to run. It quickly reveals which interfaces are down or misconfigured. For example, if a remote site cannot be reached, check the interface connecting to that site. If the Status is 'Shutdown', the interface has been administratively disabled; use 'no shutdown' to enable it. If Status is 'Up' but Protocol is 'Down', the issue is likely physical (cable, transceiver) or Layer 2 (e.g., VLAN mismatch). If both are 'Down', the interface may not be connected or the remote device is powered off. Additionally, if an interface shows 'unassigned' in the IP-Address column, it has no IPv4 address configured; this is normal for interfaces not intended for routing but can be a problem if the interface should have an IP. The command also helps identify duplicate IP addresses if you notice two interfaces with the same IP (though IOS-XR typically prevents this). For loopback interfaces, they should always show 'Up/Up' unless administratively shut down. Management interfaces (MgmtEth) are also displayed and should be 'Up/Up' for out-of-band management. In summary, this command provides a rapid health check of all IPv4 interfaces, allowing engineers to pinpoint issues before diving into more detailed diagnostics.
CCNA Exam Tips
Memorize that 'Status' refers to administrative state and 'Protocol' refers to line protocol state.
Know that 'unassigned' in the IP-Address column means no IP address is configured; this is common for interfaces not in use.
Understand that 'Shutdown' in Status means the interface is administratively down via the 'shutdown' command.
Common Mistakes
Confusing 'Status' and 'Protocol' columns: Status is administrative, Protocol is operational.
Assuming 'Up/Up' means the interface is passing traffic; it only indicates Layer 1 and Layer 2 are up.
Forgetting that management interfaces (e.g., MgmtEth) also appear in this output.
Platform Notes
In Cisco IOS-XR, the 'show ipv4 interface brief' command is very similar to its IOS counterpart, but there are key differences. The interface naming convention in IOS-XR uses a longer format (e.g., GigabitEthernet0/0/0/0) compared to classic IOS (e.g., GigabitEthernet0/0). The command is available in EXEC mode and does not require any special privileges. On IOS-XR, the output includes management interfaces (MgmtEth) by default, which may not appear in some IOS versions. Additionally, IOS-XR supports the optional parameter to specify a single interface, which is identical to IOS. There is no equivalent command for IPv6; use 'show ipv6 interface brief' instead. On other platforms like Juniper Junos, the equivalent command is 'show interfaces terse', which provides similar information but with different formatting. On Cisco IOS, the command is 'show ip interface brief' (without 'v4'). The behavior on IOS-XR is consistent across versions, but note that in earlier XR releases, the command might be 'show ipv4 interface brief' or 'show ip interface brief' depending on the version; always use the 'ipv4' variant for clarity.
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