An organization deploys an active/standby pair of network gateways configured with a First Hop Redundancy Protocol to provide default gateway resiliency. During scheduled maintenance testing, when the primary active gateway is powered off, workstations on the local subnet immediately lose all outbound internet connectivity. Inspection reveals that internal workstations are receiving traffic normally within their local LAN, but failover routing does not resume internet access until the primary gateway is powered back on. Which misconfiguration is the most likely cause of this issue?
- The workstations have their default gateway setting pointing to the physical IP address of the primary gateway rather than the shared virtual IP address.Answer
- BThe workstations are configured with a default gateway IP address that resides on a completely different logical IP subnet than their interface IP addresses.
- CThe primary gateway switchport is configured with a high numerical Spanning Tree Protocol priority value, forcing it into a blocking state.
- DThe outbound NAT rules on the secondary standby gateway are set to Static NAT instead of Port Address Translation (PAT).
Answer
The workstations have their default gateway setting pointing to the physical IP address of the primary gateway rather than the shared virtual IP address.
In high-availability network designs utilizing First Hop Redundancy Protocols (such as HSRP or VRRP), host endpoints must be configured to use the shared Virtual IP (VIP) as their default gateway. If hosts are incorrectly configured with the physical IP address of the primary router, outbound packets will continue targeting that specific physical device. Consequently, when the primary device fails or is powered down for maintenance, the secondary router cannot intercept that traffic, resulting in a complete loss of external network connectivity.
Step-by-Step Solution
Key Concept
FHRP Virtual Gateway IP Configuration