Scenario: You are a junior network engineer at Acme Corp. The company has two core Layer 3 switches (Distribution layer) connecting to a single router acting as the gateway to the internet. Management wants gateway redundancy —if the primary switch fails, users should never notice. The solution? HSRP (Hot Standby Router Protocol) .
Extend HSRP for multiple VLANs (HSRP Groups 1, 2, 3…) or configure tracking to lower priority when an upstream link fails.
show standby Expected output:
interface vlan 10 standby 1 ip 192.168.10.1 # Same group, same virtual IP standby 1 priority 100 # Lower priority = Standby standby 1 authentication md5 key-string AcmeHSRPkey exit Check HSRP status on Dist-SW1:
show standby Expected:
enable configure terminal hostname Dist-SW1 vlan 10 name USERS exit interface gigabitethernet 0/1 switchport mode access switchport access vlan 10 no shutdown interface vlan 10 ip address 192.168.10.2 255.255.255.0 no shutdown exit ip routing
enable configure terminal hostname Dist-SW2 vlan 10 name USERS exit interface gigabitethernet 0/1 switchport mode access switchport access vlan 10 no shutdown interface vlan 10 ip address 192.168.10.3 255.255.255.0 no shutdown exit ip routing Now the magic begins. You will assign the virtual IP and set the priority so Dist-SW1 becomes the Active gateway. packet tracer 9.3.3 hsrp configuration guide
Vlan10 - Group 1 State is Active 2 state changes, last state change 00:00:32 Virtual IP address is 192.168.10.1 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 1.852 secs Preemption enabled Active router is local Standby router is 192.168.10.3 Priority 150 (configured 150) Authentication MD5, key-string