[Network Security] 2.3 Secure Network Design

Network design is the basis of network security. A good network design can effectively prevent attackers from intruding. In this article, we will introduce in detail how to design a secure network, including network architecture, network equipment, network strategies, and how to handle network security incidents.

1. Network architecture

Network architecture is the basis of network design. A good network architecture can isolate different network areas and prevent attackers from moving within the network. Here are some common network architectures:

1. Flat network : A flat network is the simplest network architecture, with all devices on the same network. This architecture is easy to manage, but less secure because once an attacker enters the network, they can easily access all devices.

2. Layered Network : Layered network divides the network into multiple layers, such as core layer, distribution layer, and access layer. This architecture can improve network performance and reliability, but requires more equipment and management effort.

3. Segmented Networking : Segmented networking divides a network into multiple segments (or subnets), each with its own network devices and policies. This architecture improves the security of the network because each segment can be independently defended against attacks.

4. Virtualized Networks : Virtualized networks use software to simulate network devices and connections, which allows the network to be configured and managed more flexibly. Virtualizing a network can also improve the security of the network because virtual devices can be updated and isolated more easily.

2. Network equipment

Network devices are tools that implement network architecture and policies. Here are some common network devices:

1. Router : A router is a device that connects different networks and forwards data packets based on the destination address. Routers can be configured with access control lists (ACLs) to restrict the flow of data packets, thereby improving network security.

2. Switch : A switch is a device connected to the same network. It can forward data frames based on the MAC address. The switch can be configured with VLAN (Virtual LAN) to isolate different devices, thereby improving network security.

3. Firewall : A firewall is a device that blocks unsafe traffic. It can decide whether to allow traffic to pass based on the source address, destination address, protocol, and port of the traffic. Firewalls are the first line of defense for network security.

4. IDS/IPS : Intrusion detection systems (IDS) and intrusion prevention systems (IPS) are devices that detect and block network attacks based on traffic patterns or anomalies. IDS/IPS is an important part of network security.

3. Network strategy

Network strategy is the guiding principle for network design. Here are some common networking strategies:

1. Principle of Least Privilege : The principle of least privilege is to give devices and users only the permissions they need, not all permissions. This improves the security of your network by reducing the privileges an attacker can exploit.

2. Defense depth principle : The defense depth principle is to set up multiple layers of defense in the network instead of just one layer. This improves network security by preventing attackers from breaching all defenses at once.

3. Principle of Least Trust : The Principle of Least Trust is to not trust any device or user until they have proven their trustworthiness. This improves the security of your network by preventing attackers from exploiting trust relationships.

4. Handling network security incidents

When a security incident occurs on your network, you need to take some steps to handle the incident:

1. Discovery : First, you need to discover the event. This may be done through IDS/IPS, log analysis, or user reporting.

2. Analysis : Then, you need to analyze the nature and impact of the event. This may require viewing network traffic, system logs, or device configuration.

3. Respond : Finally, you need to respond to the event. This may be accomplished by blocking attack traffic, repairing affected devices, or updating network policies.

5. Case Study: Secure Network Design

Let's look at an example of how to design a secure corporate network.

First, we can use segmented network architecture to divide the network into several segments, such as public segment, employee segment, and management segment. The public segment can be used by guests, the employee segment can be used by employees, and the management segment can be used by IT administrators.

We can then set up different network devices and policies in each segment. The public segment can be set up with a firewall to only allow access to the Internet. You can set up a switch in the employee segment and configure VLAN to isolate different departments. The management segment can set up a router and configure ACL to restrict access.

Finally, we can set up an IDS/IPS to monitor the entire network traffic and detect and prevent any attacks. We can also set up a log server to collect and analyze all network logs to help us discover and handle any security incidents.

in conclusion

Network design is the basis of network security. A good network design can effectively prevent attackers from intruding. By understanding network architecture, network devices, network policies, and how to handle network security incidents, we can design a secure network.