show hsrp brief
Displays a summary of all HSRP groups configured on the switch, including group state, virtual IP, and active/standby routers.
Overview
The 'show hsrp brief' command provides a concise summary of all Hot Standby Router Protocol (HSRP) groups configured on a Cisco Nexus switch. HSRP is a First Hop Redundancy Protocol (FHRP) that allows two or more routers to share a virtual IP address, providing default gateway redundancy. In NX-OS, HSRP is commonly used in data center and campus networks to ensure high availability for end hosts. This command is essential for network engineers to quickly verify the operational state of HSRP groups, identify the active and standby routers, and detect any anomalies such as state flapping or misconfigurations. It is typically used after configuration changes, during troubleshooting, or as part of routine health checks. The output is a table that includes the interface, group number, priority, preempt flag, current state, active and standby router IPs, and the virtual IP. Understanding this output is critical for ensuring that redundancy is working as expected. In NX-OS, HSRP supports both version 1 and version 2, and the command works across all Nexus platforms. The brief format is ideal for a quick overview, while more detailed information is available with 'show hsrp detail'.
show hsrp brief [vrf vrf-name] [interface interface-type number] [group group-number]When to Use This Command
- Quickly verify the operational state of all HSRP groups after configuration changes.
- Identify which router is the active forwarder for a given VLAN or interface.
- Troubleshoot HSRP state flapping or preemption issues.
- Monitor HSRP group transitions during maintenance or failover testing.
Parameters
| Parameter | Syntax | Description |
|---|---|---|
| vrf | vrf vrf-name | Specifies the VRF context. If omitted, the default VRF is used. Useful in multi-VRF environments to filter HSRP groups by VRF. |
| interface | interface interface-type number | Limits output to HSRP groups on a specific interface, e.g., 'vlan 10' or 'ethernet 1/1'. Helps focus on a single link or VLAN. |
| group | group group-number | Displays information for a specific HSRP group number (0-255). Useful when multiple groups exist on the same interface. |
Command Examples
Basic HSRP Brief Output
show hsrp briefInterface Grp Prio P State Active Standby Virtual IP Vlan10 1 110 P Active local unknown 10.1.1.1 Vlan20 1 100 Standby 10.1.2.2 local 10.1.2.1 Vlan30 1 105 P Active local 10.1.3.3 10.1.3.1
Each line shows an HSRP group. The first line indicates Vlan10 group 1 with priority 110, preempt enabled (P), in Active state with local as active, standby unknown, virtual IP 10.1.1.1. The second line shows Vlan20 group 1 with priority 100, no preempt, in Standby state with active 10.1.2.2, local as standby. The third line shows Vlan30 group 1 with priority 105, preempt enabled, Active state.
HSRP Brief for a Specific Interface
show hsrp brief interface vlan 10Interface Grp Prio P State Active Standby Virtual IP Vlan10 1 110 P Active local unknown 10.1.1.1
Filters output to only show HSRP groups on Vlan10. Useful for focusing on a single VLAN.
Understanding the Output
The 'show hsrp brief' command output is a table with columns: Interface, Grp (group number), Prio (priority), P (preempt flag), State (Active, Standby, or other), Active (IP of active router), Standby (IP of standby router), and Virtual IP. The 'P' column shows 'P' if preempt is enabled, otherwise blank. The 'State' column indicates the role: 'Active' means this router is forwarding traffic for the virtual IP; 'Standby' means it is ready to take over. A healthy group should have one Active and one Standby (or more) with consistent virtual IP. Problems include 'Init' state (group not fully configured), 'Listen' (no active detected), or 'Active' with 'unknown' standby (single router). Priority values determine active election; higher priority wins. Preempt allows a higher-priority router to reclaim active role.
Configuration Scenarios
Configuring HSRP on a VLAN Interface
Two Nexus switches (Nexus-A and Nexus-B) provide gateway redundancy for VLAN 10. Virtual IP is 10.1.1.1. Nexus-A should be active with priority 110, Nexus-B standby with priority 100.
Topology
[Hosts] --- [Nexus-A] --- [Core]
|
[Nexus-B]Steps
- 1.Configure interface Vlan10 on both switches.
- 2.Set IP address on each interface (10.1.1.2/24 on Nexus-A, 10.1.1.3/24 on Nexus-B).
- 3.Enable HSRP version 2 and configure group 1 with virtual IP 10.1.1.1.
- 4.Set priority 110 on Nexus-A and 100 on Nexus-B.
- 5.Enable preempt on both switches.
! Nexus-A
interface Vlan10
ip address 10.1.1.2/24
hsrp version 2
hsrp 1
ip 10.1.1.1
priority 110
preempt
! Nexus-B
interface Vlan10
ip address 10.1.1.3/24
hsrp version 2
hsrp 1
ip 10.1.1.1
priority 100
preemptVerify: Use 'show hsrp brief' on both switches. On Nexus-A, state should be Active; on Nexus-B, Standby. Verify virtual IP is reachable.
Watch out: Ensure both switches use the same HSRP version (1 or 2). Version mismatch can prevent adjacency.
Troubleshooting with This Command
When troubleshooting HSRP issues on Cisco NX-OS, 'show hsrp brief' is the first command to run. If a group shows 'Init' state, it means the interface is down or HSRP is not fully configured. Check interface status with 'show interface'. If the state is 'Listen', the router is not hearing hellos from an active router; verify IP connectivity and that both routers are on the same subnet. If the active router shows 'unknown' standby, either the standby router is not configured or there is a communication issue. Check for ACLs blocking UDP port 1985 (HSRPv1) or 1985/1986 (HSRPv2). Also verify that both routers have the same virtual IP and group number. If preempt is not working, ensure the 'preempt' command is configured and that the priority values are correct. Use 'show hsrp detail' to see timers and hello statistics. In NX-OS, HSRP can also be affected by VRF configuration; ensure the VRF is consistent. If the group is flapping between Active and Standby, check for interface flaps or high CPU. Use 'show logging' to see HSRP state changes. For multicast issues, verify that IGMP snooping is not filtering HSRP hellos; HSRPv1 uses 224.0.0.2, HSRPv2 uses 224.0.0.102. Finally, ensure that the virtual IP is not used elsewhere on the network.
CCNA Exam Tips
Remember that 'P' indicates preempt is enabled; without it, a higher-priority router won't take over after a failback.
The 'Active' and 'Standby' columns show IP addresses; 'local' means the local router is in that state.
Know that HSRP uses UDP port 1985 and multicast 224.0.0.2 (version 1) or 224.0.0.102 (version 2).
Common Mistakes
Confusing 'Active' and 'Standby' states; Active forwards traffic, Standby monitors.
Assuming 'unknown' standby always indicates a problem; it can occur if only one router is configured.
Forgetting that HSRP priority is only compared within the same group; groups are independent.
Platform Notes
On Cisco NX-OS, the 'show hsrp brief' command is similar to Cisco IOS but with some differences. NX-OS uses the 'hsrp' command under interface configuration, while IOS uses 'standby'. In NX-OS, HSRP version 2 is the default for new configurations, whereas IOS defaults to version 1. NX-OS also supports HSRP over VXLAN and in ACI environments. The output format is consistent across Nexus 9000, 7000, and 3000 series. For equivalent commands on other platforms: on Juniper Junos, use 'show hsrp summary'; on Arista EOS, use 'show ip hsrp'. On Cisco IOS, the command is 'show standby brief'. NX-OS also supports 'show hsrp statistics' for packet counters. Note that NX-OS does not support HSRP on Layer 2 interfaces; it must be configured on SVI (VLAN interfaces) or routed ports.
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