In modern enterprise environments, the local area network (LAN) is one of the critical infrastructures supporting daily business operations.

However, as the network scale continues to expand and technology advances, LANs face increasing technical challenges.

Among these, IP address conflicts and network performance degradation are the most common issues, which not only lead to network service interruptions but also affect work efficiency.

Moreover, many enterprises have built comprehensive office information systems and deployed video surveillance to enhance security management and information level.

However, due to a lack of overall planning or inadequate consideration when selecting network products, network construction often fails to meet expectations, leading to many application issues.

Today, let’s discuss these common problems and see if you’ve encountered any of them.

01 Slow Network Cloning Speed

In LANs, network cloning typically refers to the process of quickly copying the operating system and applications from one computer to multiple computers. This process is crucial for batch deploying new devices or updating existing ones.

However, in practice, slow network cloning speed is a common issue that directly affects work efficiency and network resource utilization.

01 Cause Analysis

• Hardware Limitations: Slow network interface cards (NICs) or outdated network devices limit data transfer rates.
• Network Bottlenecks: Certain network segments may become bottlenecks for data transmission, such as insufficient switch port speeds or limited router processing capabilities.
• Improper Network Configuration: Incorrect network configurations, such as inappropriate subnet divisions or unreasonable network traffic management strategies, can also lead to slow network cloning speeds.

02 Solutions

• Upgrade Hardware: Replace slow NICs with high-speed ones and use switches and routers that support gigabit or 10-gigabit transmission rates.
• Optimize Network Configuration: Plan subnets reasonably to avoid unnecessary network segmentation; adjust network traffic management strategies to ensure bandwidth priority during cloning.
• Adopt Efficient Cloning Techniques: Use PXE (Preboot Execution Environment) boot technology for network cloning to reduce reliance on local storage; use differential cloning technology to speed up the cloning process.

02 Switch Loops Causing Network Collapse

In LANs, switches are key components connecting various devices. When network topology design is improper or configuration errors occur, loops may form, leading to severe network issues and even network collapse.

Switch Loops Causing Network Collapse

01 Causes

• Incorrect Network Cabling: Incorrect physical connections, such as two cables connecting the same set of ports.
• Redundant Connections: Redundant paths set up for network availability are not properly configured.
• Configuration Errors: Improper switch port configurations, such as enabling unnecessary ports or incorrect VLAN settings.

02 Solutions

• Enable STP (Spanning Tree Protocol): By enabling Spanning Tree Protocol, loops can be prevented as the protocol automatically shuts down redundant links in loops.
• Optimize Network Topology: Re-evaluate network topology design, remove unnecessary redundant connections, and simplify network structure.
• Avoid Unnecessary Redundant Connections: Only establish redundant paths when necessary and ensure they do not form loops.

03 Small Routers in LANs Causing IP Address Conflicts

In LANs, IP address conflicts usually occur when two or more devices are assigned the same IP address. This situation can lead to unstable network connections or some devices being unable to access the network.

01 Causes

• Manual Configuration Errors: Administrators make mistakes when manually configuring IP addresses, assigning the same address to multiple devices.
• DHCP Server Failures: Dynamic Host Configuration Protocol (DHCP) servers have issues, such as configuration errors or software failures, leading to duplicate IP address assignments.
• Small Router Limitations: Small routers may lack advanced features, such as fine-grained address management or conflict detection mechanisms, easily causing conflicts.

02 Solutions

• Check and Fix DHCP Configuration: Ensure DHCP servers are correctly configured, troubleshoot faults, and plan address pool ranges reasonably.
• Use Static IP Addresses: For critical devices, consider manually assigning static IP addresses to avoid conflicts.
• Enhance Router Capabilities: Upgrade to routers with stronger address management and conflict detection capabilities.

04 LAN Suffering from ARP Virus Attacks

ARP (Address Resolution Protocol) virus attacks are common network attack methods that forge ARP responses to alter the mapping between IP addresses and MAC addresses within the LAN, aiming for man-in-the-middle attacks. Such attacks can lead to data leakage, service interruptions, and other issues.

01 Attack Principles

• ARP Cache Poisoning: Attackers send forged ARP responses to the target network, binding their MAC address with the target IP address, causing other devices in the network to send packets to the attacker instead of the real target device.
• Man-in-the-Middle Attacks: Once the attacker successfully inserts themselves into the communication path between the source and target devices, they can eavesdrop, tamper with, or block packet transmissions.

02 Solutions

• Install Antivirus Software: Use reliable antivirus software to detect and remove ARP viruses.
• Regularly Update Security Policies: Ensure network device firmware and operating systems are up-to-date and follow best security practices.
• Use Static ARP Tables: Manually create static ARP entries, binding the IP addresses of critical devices with their MAC addresses to prevent ARP cache poisoning.
• Enable ARP Protection Features: Many modern switches and routers support ARP protection features, such as ARP Inspection or DAI (Dynamic ARP Inspection), to verify the validity of ARP responses.

05 Office Network Overloaded by Monitoring Data

In modern office environments, network monitoring is a necessary measure to ensure network security and compliance. However, excessive monitoring data collection can occupy a large amount of network bandwidth, affecting the performance of normal business applications.

01 Impact of Data Monitoring

• Network Bandwidth Occupation: Continuous data monitoring generates a large amount of monitoring data streams, which need to be transmitted over the network to monitoring centers or log servers.
• Computing Resource Consumption: Collecting and processing monitoring data requires additional computing resources, such as CPU and memory, which may affect other server tasks.

02 Solutions

• Adjust Monitoring Strategies: Optimize monitoring frequency and data collection scope, only monitoring necessary information to reduce unnecessary data traffic.
• Increase Bandwidth Resources: If monitoring data indeed occupies a large amount of bandwidth, consider increasing network bandwidth to ensure sufficient resources for other business uses.
• Use Dedicated Monitoring Networks: Consider setting up independent network channels for monitoring data to avoid competing with business traffic for bandwidth.
• Optimize Data Processing: Use more efficient algorithms and technologies to process monitoring data, reducing server resource consumption.