A New Way to Control Access in the Zero Trust Era : TiFRONT ZT ACL

Beyond Complexity, Toward Simplified Security

Today’s network environments are becoming increasingly complex due to rapid scale expansion and service diversification. As a result, traditional ACL (Access Control List) management approaches are reaching their operational limits. When hundreds or even thousands of ACL rules are scattered across multiple devices, CLI (Command Line Interface)-based ACL management not only reduces operational efficiency but also increases the risk of configuration errors and policy conflicts—ultimately placing a heavy burden on network operations. 

TiFRONT ZT ACL (hereafter referred to as “ZT ACL”) is an access control solution designed on a Zero Trust architecture to address these challenges. By centrally managing ACLs distributed across security switches through the TiController ZT platform, ZT ACL significantly reduces management complexity while strengthening overall security. 

Limitations of L2 Switch ACLs

ACL operating on L2 switches face several limitations in complex network environments: 

● Host-based ACL Operation
ACL rules must be applied individually to each endpoint(MAC/IP address). As the number of endpoints increases, the number of ACL rules grows exponentially, increasing administrative workload and the risk of errors. 

● Hardware Filter Resource Limitations
Hardware filter (H/W filter) resources within switches are limited. Creating rules on a per-endpoint basis rapidly consumes these resources, limiting scalability. 

● Increased Operational Complexity
Manual CLI-based configuration is labor-intensive and does not provide a unified, network-wide view. As a result, maintenance and troubleshooting become more difficult. 

Challenges of Managing ACLs on L2 Switches

Configuring and operating ACL policies on L2 switches is complex and inefficient due to functional limitations and the management complexity of distributed network environments. For these reasons, ACLs on L2 switches are typically used as a supplementary feature for simple access control, while NAC (Network Access Control) solutions and firewalls are used to control access to critical resources. 

● NAC (Network Access Control)
NAC identifies and authenticates users and devices connecting to the network and controls access based on their security posture. In addition to IP/MAC-based control, it enables granular policy enforcement based on user credentials, device type, OS patch level, and security agent installation status. 

● Firewall
Firewalls are core security devices that control traffic between internal and external networks at the perimeter. Beyond basic IP and port filtering, they analyze application-layer traffic and block malware and threats, enabling centralized security policy management. 

1. Functional Limitations

■ Primary Role of L2 Switches
L2 switches control frames based on data link layer information such as MAC addresses, VLAN IDs, and Ethernet types. This limits their ability to implement sophisticated security policies based on L3/L4 information such as IP addresses and port numbers. 

■ Limited Filtering Criteria
L2 ACLs mainly operate on L2 header information, including MAC addresses, VLAN IDs, and Ethernet types. Fine-grained filtering using IP addresses or TCP/UDP ports (L3/L4) is either unsupported or very limited compared to L3 switches or firewalls. As a result, implementing complex policies—such as controlling specific application traffic or blocking access to certain IP ranges— is difficult. 

■ Hardware Resource (TCAM) Constraints
Switches store ACL policies in hardware (TCAM, Ternary Content Addressable Memory) for high-speed processing. However, L2 switches generally have smaller TCAM capacities than L3 switches. As the number of ACL policies increases, storage shortages and performance degradation can occur.    

2. Management Complexity

■ Port-based Management
L2 switch ACLs are applied on a per-port basis. As the network scales, policies must be configured and maintained individually for each port, significantly increasing management complexity. 

■ Lack of Policy Synchronization and Logging
In environments with multiple switches, ensuring policy synchronization is difficult, and logging and monitoring capabilities for ACL operations are limited. This leads to higher operational costs for troubleshooting and compliance. 

■ Challenges in DHCP Environments
In DHCP-based environments, endpoint IP addresses change dynamically, causing mismatches between policies and endpoints. Administrators must continuously modify or redeploy ACLs, significantly reducing management efficiency. 

Due to these limitations, managing complex or large-scale ACL policies on L2 switches is inefficient and insufficient for serving as a core network security mechanism. Therefore, centralized security policy management using L3 switches or dedicated firewalls is generally recommended. 

Advantages of ZT ACL

ZT ACL overcomes the structural limitations of traditional ACLs by providing centralized policy management and a scalable access control framework. 

● Centralized Policy Management
TiController ZT enables centralized management of ACL policies across all security switches. Its GUI-based policy creation and deployment environment reduces operational errors, minimizes the risk of policy omissions, and ensures consistency and unified visibility across the network. 

● Segment-based Access Control
Policies are defined by logical segments—such as departments, business functions, or resource types—rather than individual endpoints. This greatly improves management efficiency while minimizing hardware resource consumption and enabling easy application of the principle of least privilege across the network. 

● Operational Simplicity and Scalability
As the number of clients increases, administrators only need to manage segment-based policies, ensuring scalability while keeping management complexity low. 

● Optimized for Zero Trust Implementation
Policies can be defined based on logical attributes such as users, devices, departments, and workloads, enabling effective enforcement of the principle of least privilege and limiting lateral movement. 

● Simulation Mode
A simulation mode allows administrators to verify policy effects and impact scopes before deployment. Log-based validation in detection mode helps prevent service disruptions caused by policy misconfigurations. 

● Tag-based Access Control
Meaningful tags such as “Sales Department,” “Development Server,” or “Shared Printer” can be used to apply policies. Automatic tag mapping preserves policy structures even as the network environment changes, significantly improving operational efficiency. 

Strengthening Internal Network Security with ZT ACL

ZT ACL applies microsegmentation concepts to enable comprehensive control of the entire network based on network visibility. By actively enforcing access control to resources, it significantly strengthens internal network security. 

The Client–Resource Map feature of TiController ZT provides real-time visibility into connections between clients and resources. Administrators can instantly see who(user), using which device(client), is accessing which resource. 

In the Client–Resource Map, the inner circle represents users(sources), while the outer circle represents resources(destinations). By selecting a specific user, administrators can immediately identify the resources accessed by that user. 

ZT ACL: Practical Implementation of Zero Trust

ZT ACL goes beyond simple packet filtering by enabling centralized policy management and automated policy deployment, delivering a practical implementation of the Zero Trust security model. By overcoming the limitations of manual, CLI-based ACL operations, ZT ACL delivers three core values: Ease of Management, Policy Consistency, and Automation—establishing a new paradigm in network security management. 

Instead of struggling with complex command-line configurations, administrators can now achieve maximum security effectiveness with minimal effort through the intuitive TiController ZT interface. As network complexity continues to increase, ZT ACL becomes an essential component for reducing operational burden while building a robust and secure network environment.