Wireless LAN Security Guidelines

Ministry of Internal Affairs and Communications (MIC): Wireless LAN (Wi-Fi) Security Guidelines

The MIC's Cybersecurity Policy Office publishes guidelines for both users and providers on the safe and secure use of wireless LAN (Wi-Fi).

Without adequate security measures, using wireless LAN may expose your communications to eavesdropping and other risks. Please refer to these guidelines to strengthen your understanding of security measures and use wireless LAN safely.

  • Quick Guide for Home Wi-Fi Users
  • Quick Guide for Public Wi-Fi Users
  • Security Measures Handbook for Public Wi-Fi Providers
  • Online Course on Wireless LAN (Wi-Fi) Security Measures

About Radio Waves

Compared to wired LAN, wireless LAN offers greater flexibility in where you can connect — but you may also experience issues such as slow speeds, unstable connections, or sudden loss of connectivity. When installing or using APs, please keep the following characteristics and interference factors in mind.

  • Signal strength decreases as distance from the AP increases.
  • Signals travel in a straight line when unobstructed, but in practice are affected by buildings, metal, water, and other materials.
  • Radio signals can interfere with one another.

Radio Interference

Many connection problems are caused by device-specific issues or radio interference. Radio interference occurs when Wi-Fi signals and signals from appliances such as microwave ovens or mobile routers interfere with each other, causing an unstable connection. This can result in symptoms such as slow speeds, intermittent connectivity, or complete disconnection. Common sources of interference include:

  • Smart home appliances
  • Microwave ovens
  • IH cooking heaters (induction cooktops)
  • Bluetooth devices / other 802.11 networks
  • Wireless products
  • Mobile routers / pocket Wi-Fi
  • Cordless phones
  • Radar
  • Perimeter sensors
  • Digital satellite equipment

Reference: Meraki — Common Sources of Wireless Interference

Radio interference cannot be eliminated entirely. To minimize its impact, the organization managing the AP installation location should consider the following measures:

  • Increase distance from interference sources.
    • Move away from home appliances and other wireless LAN devices.
    • Try to avoid excessive crowding of users and devices in the same area where possible.
  • Change the channel of interfering devices.
    If your organization has installed a wireless LAN router in the same room as an AP (e.g., a laboratory, office, or meeting room), changing the channel may improve stability.
  • Switch to a different frequency band.
    If you experience connection issues on your device, try selecting a different frequency band. The 2.4 GHz band is more prone to interference than the 5 GHz band.

Signal Strength and Channel Adjustment

The campus wireless LAN uses Meraki's automatic settings for signal strength and channel allocation. Please note that individual adjustments cannot be accommodated.

If your organization operates its own wireless LAN router in a laboratory or office, this may cause interference and affect communication quality. Please consider changing the placement or channel of your wireless router within your organization.

About Wireless LAN Site Surveys

If you are experiencing wireless LAN instability, please check the usage location and time-of-day conditions — either as an individual user or as the organization managing the relevant area. Reference: Radio Interference

For reference, if the room's managing organization contacts us, we may be able to provide the channel utilization rate and interfering SSID names observed at a given point in time. However, please note that this is real-time information captured at the moment of investigation — we cannot specify dates or times for investigation, nor can we take action on interfering signals (such as identifying the managing organization, contact person, or specific device). Please conduct your own investigation and handle the situation within your organization.

If you wish to commission an external wireless LAN site survey, the requesting organization is responsible for handling the entire process.
※ Examples of what the requesting organization handles: finding a vendor, defining the scope of work, coordinating with relevant parties (room manager, users, NOC), and covering all associated costs.