NETWORK SECURITY OPTIMIZATION USING VLAN, FIREWALL, AND ACL AT PT. ANDALAN NIAGA EXPRESSINDO

Abstract

PT. Andalan Niaga Expressindo (ANX), an international freight-forwarding company, currently runs a computer network without VLAN segmentation or an Access Control List (ACL), so all divisions share one broadcast domain with unrestricted inter-division access, raising the risk of unauthorized access to company data. This study designs a division-based VLAN scheme for four divisions (HRGA & Accounting, Document, Sales, and Customer Service), combined with Router-on-a-Stick inter-VLAN routing, a DHCP server, an ACL restricting inter-VLAN access, and a firewall filtering internal-external traffic. All configuration, implementation, and testing were carried out entirely within the Cisco Packet Tracer simulation environment, not on the company's production network. Twenty-four test scenarios were executed, covering VLAN activation status, inter-VLAN connectivity, DHCP address allocation, ACL permit/deny behavior in both directions, and firewall rule matching for internal-to-external, external-to-internal, and service-specific traffic. Results show the four VLANs were successfully activated, inter-VLAN routing worked as configured, the DHCP server correctly allocated addresses per division, the ACL correctly permitted and denied traffic according to the configured direction and rule, and the firewall correctly matched traffic against its configured rules. Within this simulation, the design demonstrated improved access control between divisions and is expected to improve network security and administrative efficiency if applied to the actual network, pending validation on physical devices. This research contributes an integrated, simulation-tested design combining VLAN, inter-VLAN routing, a DHCP server, an ACL, and a firewall for a freight-forwarding company network, an integration not jointly examined in the reviewed prior studies.