HSRP Wrong Router as Active Due to Misconfigured Priority
Presenting Symptom
The HSRP standby router is acting as the active router, causing suboptimal traffic flow and potential connectivity issues.
Network Context
A small branch office with two Cisco Catalyst 2960 switches (SW1 and SW2) acting as HSRP gateways for VLAN 10. Both run IOS 15.2. The network has a single VLAN 10 with hosts using HSRP virtual IP 10.0.0.1. SW1 is intended to be the active router, but SW2 is active instead.
Diagnostic Steps
Check HSRP status on both routers
show standbySW1:
Vlan10 - Group 1
State is Standby
1 state changes, last state change 00:05:12
Virtual IP address is 10.0.0.1
Active virtual MAC address is 0000.0c07.ac01
Local virtual MAC address is 0000.0c07.ac01
Hello time 3 sec, hold time 10 sec
Next hello sent in 1.024 secs
Preemption enabled
Active router is 10.0.0.3, priority 100 (expires in 8.192 sec)
Standby router is local
Priority 90 (configured 90)
Group name is "hsrp-Vl10-1"
SW2:
Vlan10 - Group 1
State is Active
2 state changes, last state change 00:10:00
Virtual IP address is 10.0.0.1
Active virtual MAC address is 0000.0c07.ac01
Local virtual MAC address is 0000.0c07.ac01
Hello time 3 sec, hold time 10 sec
Next hello sent in 0.256 secs
Preemption enabled
Active router is local
Standby router is 10.0.0.2, priority 90 (expires in 8.192 sec)
Priority 100 (configured 100)
Group name is "hsrp-Vl10-1"SW1 shows priority 90 and is standby; SW2 shows priority 100 and is active. This indicates SW2 has higher priority, but SW1 should be active. Check configured priorities.
Verify HSRP configuration on both routers
show running-config | section interface Vlan10SW1: interface Vlan10 ip address 10.0.0.2 255.255.255.0 standby 1 ip 10.0.0.1 standby 1 priority 110 standby 1 preempt SW2: interface Vlan10 ip address 10.0.0.3 255.255.255.0 standby 1 ip 10.0.0.1 standby 1 priority 100 standby 1 preempt
SW1 has priority 110 configured, but show standby shows priority 90. This mismatch indicates the configuration may not have been applied correctly or was overwritten. Check for any interface-level override or global default.
Check for interface-level priority configuration
show standby Vlan10SW1: Vlan10 - Group 1 State is Standby Priority 90 (configured 90) ...
The configured priority is 90, not 110 as in running-config. This suggests the running-config may have been changed after the show standby output was captured, or there is a mismatch. Re-check the running-config carefully.
Re-examine running-config for any priority override
show running-config interface Vlan10 | include standbystandby 1 ip 10.0.0.1 standby 1 priority 110 standby 1 preempt
The running-config shows priority 110. The show standby output shows priority 90. This inconsistency indicates that the running-config was modified but not applied to the interface (e.g., the interface was not shut/no shut or the standby group was not re-initialized). Alternatively, there might be a typo in the configuration (e.g., 'standby 1 priority 90' was entered elsewhere).
Check for any global or interface-specific standby settings
show standby briefInterface Grp Pri P State Active Standby Virtual IP Vl10 1 90 P Standby 10.0.0.3 local 10.0.0.1
The priority is 90, confirming the mismatch. The root cause is that the priority configuration is not taking effect. This could be due to the interface being in a different VRF or the standby group not being properly initialized.
Root Cause
The HSRP priority on SW1 was configured as 110 in the running-config, but the actual priority in the HSRP process is 90. This discrepancy occurs because the interface Vlan10 was not properly re-initialized after the priority change, or the configuration was applied to a different interface (e.g., subinterface). In this case, the configuration was applied to the correct interface but the standby group did not reload the new priority due to a missing 'standby 1 priority 90' command being present elsewhere (e.g., in a different config snippet) that overrides the intended 110. The actual root cause is that the priority was misconfigured as 90 on SW1, making SW2 (priority 100) the active router.
Resolution
Verification
After applying the fix, run 'show standby' on SW1: Vlan10 - Group 1 State is Active Priority 110 (configured 110) Active router is local Standby router is 10.0.0.3, priority 100 This confirms SW1 is now active with priority 110.
Prevention
1. Always verify HSRP priority after configuration changes using 'show standby'. 2. Use a consistent priority scheme and document intended active/standby roles. 3. Enable preemption to allow automatic failback when the higher priority router recovers.
CCNA Exam Relevance
On the CCNA 200-301 exam, this scenario appears in troubleshooting questions where you must identify why the wrong HSRP router is active. The exam tests understanding of HSRP priority, preemption, and the 'show standby' command. Key fact: The router with the highest priority becomes active; if priorities are equal, the highest IP address wins.
Exam Tips
Memorize the 'show standby' output fields: priority, state, active router, standby router.
Remember that HSRP priority is configured per interface under the interface configuration mode.
Understand that preemption must be enabled for a higher priority router to take over after a failure.
Test Your CCNA Knowledge
Practice with scenario-based questions to prepare for the CCNA 200-301 exam.
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