Question 130
A company wants VLAN 90 clients to reach a server in VLAN 100. VLAN trunks work and each VLAN has its own IP subnet, but there is no routed gateway between them. Which configuration enables the required traffic?
Explanation
Correct Answer
VLANs are distinct broadcast domains, so packets destined for another subnet require a routing function. A multilayer switch can create gateway SVIs for VLAN 90 and VLAN 100 and route between them, or a router-on-a-stick can supply subinterfaces. Proper host default gateways and ACL policy must also support the path.
Incorrect Answers
802.1Q trunking preserves VLAN identities across links but keeps their Layer 2 traffic separate. Carrying both VLANs does not by itself produce a Layer 3 next hop between their subnets.
Port security limits which MAC addresses are accepted on a port; it does not create inter-subnet routing. It may protect the server edge, but the missing function is a router gateway.
Spoofing MAC addresses cannot make two IP subnets route across VLAN boundaries and risks confusing switch forwarding tables. Address duplication is not a valid gateway substitute.