Even though you are connected to Wi-Fi at school or work, you can't send LINE messages or receive Discord notifications... Have you ever experienced that? You may think, "Why, even though there is radio waves?", but in reality, in most cases, the network is intentionally blocking the communication of a specific app.

In this article, based on information as of March 2026, we will explain in an easy-to-understand manner how certain apps can no longer be used on Wi-Fi at school or work, and four ways to deal with the issue on your smartphone.

Why can't I use certain apps on Wi-Fi at school or work?

The bottom line is that the network administrator has applied filtering (communication restrictions). Whether it's a school or a company, the Wi-Fi provider has some control over who is communicating and what kind of communication.

Roughly speaking, app communication is blocked in the following three ways.

1. Port blocking

Internet communication passes through numbered gateways called "ports." Browsing websites uses port 443 (HTTPS), but LINE and Discord may also use other proprietary ports. If the administrator closes these ports, only the app's communication will not be able to pass through.

2. DNS filtering

DNS (Domain Name System) is a mechanism that converts domain names such as "discord.com" into IP addresses. Wi-Fi at school or work may block access to certain domains at this DNS stage. In other words, when the app tries to find the server location, it returns "No such location".

3. Application level filtering

Nowadays, firewalls (systems that monitor and control communications) have become smarter, and they can look at the content of a communication and determine whether ``this is a LINE communication'' or ``this is a Discord communication.'' Filtering products for the GIGA School Initiative (InterSafe, i-Filter, etc.) generally have settings that block entire categories such as "SNS" and "Chat."

The Ministry of Education, Culture, Sports, Science and Technology's "School Network Improvement Guidebook (June 2020 Edition)" also recommends the introduction of filtering on students' devices. The reason you can't use apps on school Wi-Fi is because it's designed that way for security reasons.

How to check if you are blocked

If you're wondering, "Is it really blocked? Or is it just a glitch?", use the following method to check.

Turn off Wi-Fi and try using mobile data

This is the simplest confirmation method. Try turning off Wi-Fi from your smartphone's settings and switching to 4G/5G mobile data communication. If you can send and receive data using mobile data but not using Wi-Fi, it is very likely that the Wi-Fi network is blocking it.

Try accessing the website with a browser

Try to see if you can open Google searches and news sites normally from your browser while connected to the same Wi-Fi. If you can view the web but can't use apps, there are communication restrictions on an app-by-app basis.

Try other apps

In addition to LINE, try multiple apps such as Discord, Instagram, and YouTube. If you want to say, "I can't use all SNS, but I can use the web," filter by category. If "Discord only doesn't work", a specific port or domain may be blocked.

Four ways to deal with it yourself

Once you have confirmed the block, try the following method.

Countermeasure 1: Switch to mobile data communication (most reliable)

The simplest and surest way is to turn off Wi-Fi and use your smartphone's mobile data (4G/5G). Network restrictions at schools and workplaces only apply to communications via Wi-Fi, so mobile data is not affected.

However, data communication will be required, so be careful about consuming gigabytes if you watch a lot of videos or send/receive files. For peace of mind, check the data capacity of your contracted plan.

Countermeasure 2: Use tethering (mobile hotspot)

If you use the tethering function of your smartphone, you can also communicate with your PC or tablet via mobile data. If you are using an iPhone, you can set it up by going to "Settings" → "Internet Sharing", or if you are using Android, go to "Settings" → "Network & Internet" → "Access Points & Tethering".

This method is useful if you want to use the web versions of Discord or Slack on your school-issued Chromebook or work PC. However, some organizations prohibit the use of personal tethering on company-issued PCs, so check your company's policies before trying it out.

Solution 3: Try the web browser version

Many services have web versions that can be used from a browser.

Even if app communication is blocked, web communication via port 443 (HTTPS) is often allowed, so there are cases where the browser version can be used. However, if the entire domain is blocked by DNS filtering, this method will not work.

Solution 4: Change the DNS server (for advanced users)

If Wi-Fi is blocked by DNS filtering, you may be able to avoid it by changing the DNS settings on your smartphone or PC.

For iPhone:

  1. Open “Settings” → “Wi-Fi”
  2. Tap "i" to the right of the network name you are connected to
  3. Change "Configure DNS" to "Manual"
  4. Delete existing DNS server and add "8.8.8.8" and "8.8.4.4" (Google Public DNS)

For Android:

  1. Settings → Network and Internet → Private DNS
  2. Select "Private DNS provider hostname"
  3. Enter "dns.google" and save

However, this is only useful for DNS level filtering. It has no effect if blocked through a firewall or proxy. Also, avoid changing on work devices as it may violate your organization's security policy.

Bad actions that should not be done

I understand that you want to avoid network restrictions, but please avoid the following actions as they are risky.

Using a VPN without permission

You can get around many restrictions by using a VPN (Virtual Private Network), but the terms of use of schools and companies often explicitly prohibit unauthorized use of a VPN. In the case of GIGA school terminals, according to Trend Micro research, attempts to evade security measures themselves may be subject to monitoring. If discovered, it may lead to disciplinary action and the removal of your device.

Connect to a free Wi-Fi spot

You can circumvent the restriction by connecting to free Wi-Fi at a nearby cafe or convenience store, but Free Wi-Fi is often unencrypted, so there is a risk of eavesdropping on communications. Communication containing business data or login information is particularly dangerous.

Change administrator settings without permission

It is absolutely no good to use the administrator password to change proxy settings or firewall settings on school-issued terminals or work PCs. This may be considered unauthorized access.

What if I still want to use the app?

If an application that is absolutely necessary for your business is restricted, the best solution is to consult with your IT administrator.

  • For schools: Tell your homeroom teacher or information teacher the specific reason, such as ``I want to use Discord in 〇〇 class.'' GIGA School filtering can be set by the administrator to allow specific URLs and apps individually
  • In the workplace: Report to the information systems department that ``communications of apps used for work are restricted.'' If there is a valid reason, you may be added to the allowed list (whitelist)

For private purposes, it is best to use mobile data communication. The least troublesome method is to turn off Wi-Fi and check LINE during breaks.

FAQ

Is it illegal to not be able to use LINE on school Wi-Fi?

It's not illegal. Network administrators have the authority to set the usage range of the provided Wi-Fi. For schools, filtering is in accordance with the guidelines of the Ministry of Education, Culture, Sports, Science and Technology.

Is it okay to install an app to bypass Wi-Fi blocks?

You may be able to avoid this using a VPN app, but it is likely to violate the terms of service of your school or workplace. Please avoid this at all costs, especially on supplied terminals.

Why can't I use the app even after switching to mobile data?

If you cannot use mobile data, there may be a problem with the app itself or your account. Try restarting and reinstalling the app.

How much data does it cost to use tethering?

The amount of text sent and received on LINE is very small, only a few KB per message. However, when sending and receiving images/videos and making calls, consumption increases. A one-hour LINE call will take approximately 300MB.

Will school Wi-Fi restrictions change once spring break begins?

Filtering rules may change during long holidays. There are also reports of cases where rules become stricter (or more relaxed) during the new school year.

References