WiFi at full capacity but no internet access? The phone prompts you that you can't access the internet. Follow these 5 steps to find the real culprit in 5 minutes

One night last month, my wife suddenly shoved her phone over: "The WiFi is connected, why can't I play Douyin?" I checked—the signal was full, an exclamation mark hanging next to the icon, WeChat was spinning in circles, and the webpage wouldn't open. I've encountered this kind of thing more than ten times over the years—sometimes it's the router's fault, sometimes the optical modem's fault, and one time it was even the phone's own fault.

many people, when encountering "WiFi is connected but no internet," their first reaction is to restart the router. If restarting doesn't work, they restore the factory system, which only messes up the network further. Actually, there's a fixed pattern for troubleshooting this issue. You just need to understand one thing: network travels from the optical modem to the router and then to your phone, moving through segments one by one. If a segment fails, it is completely disconnected. Fix the that segment that breaks off. The following five steps are the order in which I personally set the trap, starting from the most common ones, and basically you can locate them within 5 minutes.

: Take 30 seconds to tell whether one device has no internet or if the whole family has no internet

This is the most crucial step, directly determining which direction you will search next. Pick up another phone at home, or connect your computer to WiFi and casually open a webpage to try.

my situation that day: my Redmi Note 12 works fine, but my wife's phone doesn't. This means the router, fiber modem, and broadband are all fine. The problem lies with her own phone, and the direction of the search is completely different afterward. Conversely, if none of your devices at home have internet access and every WiFi icon has an exclamation mark, it means the broadband or router section is disconnected, and you jump straight to step two.

there's a middle ground: your phone can access WeChat and send and receive messages, but web pages won't open. WeChat uses its own long connections, while webpages use DNS resolution. This kind of "half-dead" status is probably a DNS issue. You can skip to step four.

Two: If your whole family has no internet, first check the lights on the optical modem and router

Don't rush to act, look at the lights first." The lights are the most honest statement of the equipment. My optical modem is a ZTE F7015T, and my router is a ZTE Xuntian AX3000. Just using these two as a reference, other brands' lights follow a similar logic.

the light modem looks at two lights: PON and LOS. The PON light stays on and green, indicating the fiber is registered normally; the LOS light flashes red, meaning the optical path is broken. It could be due to the fiber being bent or a faulty splitter in the community. If you can't fix this yourself, just call the carrier to report the repair. How much light degradation is considered normal, and what color each light represents—I've written a detailed article before. You can check it out: on the self-check of the light modem indicator light.

the modem lights are normal, then check the router. Check the status of the WAN port in the backend after logging in. If it shows "Not Connected" or keeps "Connecting," it means there is a dialing problem. I've encountered this twice: once for overdue broadband bills. When the mobile service center checked, I was in debt of over thirty yuan, and after paying, it automatically recovered after waiting two minutes; Another was a verification failure on the carrier's side; restarting the optical modem and dialing again fixed the issue. For a detailed investigation of router dialing issues, you can refer to my previous article about dialing WAN ports.

here's a clever trick many people don't know: connect the optical modem directly to the computer for testing. One end of the network cable is plugged into the optical modem port 1 (note: port 1 is the same as my F7015T only has gigabit port 1). Plug one end into the computer, and enter your account and password for broadband dial-up on the computer. If you can dial it, it's a router issue; if not, it's a broadband issue. One cable can clear the responsibility, so repairs are targeted and you won't be tricked by customer service to "try restarting the router."

Step 3: Only one phone has no internet. Check the IP address it obtained

a single device is disconnected, the most common reason is a DHCP malfunction. After connecting your phone to WiFi, it will ask the router for an IP address, and you can only access the internet once it's there. How to check: In your phone's settings, open the currently connected WiFi device, scroll down, and check the IP address section.

normally it should start with 192.168 (my router is 192.168.31.1, which splits it down to 192.168.31.x). If what you see is a string of addresses starting with 169.254 , congratulations, the problem has been found: the phone didn't get a valid IP from the router. 169.254 is an "invalid IP" the phone created for itself, so of course you can't access the internet with this address.

solution is clever but effective: click "Forget this network" in the WiFi details, then re-enter the password to reconnect and let your phone go through the IP application process again. That's exactly how my wife's phone was made that day. If that doesn't work, turn off the WiFi switch and turn it back on; if that doesn't work, restart the phone—don't laugh, restarting your phone is truly a great solution to Android network stack issues.

if you forget to reconnect and still get 169.254, log in to the router's backend to check if the DHCP service is disabled or if the address pool is too small and has already been split. One time when I was fiddling with a soft router, I accidentally turned off DHCP on the main router. The whole family's devices were all 169.254, and the scene was truly spectacular.

Four: WeChat can be accessed but cannot be opened online; switching DNS will make an immediate difference

DNS simply put, it's a 'URL translator' who translates www.baidu.com into IP addresses. Translators went on strike, but apps like WeChat, which remembered IP addresses, still ran, while the web pages were completely abandoned. The method to judge is simple: WeChat can send and receive messages, but the browser cannot open any websites—this is textbook-level DNS failure.

changing DNS on your phone is very fast. Take Android as an example: Set → WLAN → Click on Current WiFi Details → Change IP settings to "Static" or "IPV4 settings," change DNS to 223.5.5.5 (Alibaba's) or 119.29.29.29 (Tencent), leave other options unchanged, and save. I tested it after modifying and refreshing the webpage, and it opened instantly. Another typical symptom is that the DNS configuration is incorrect and web pages loading very slowly and videos scrolling in circles. I wrote more detailed explanations in of DNS article.

by the way, routers can also globally change DNS in the background, so every change benefits all your family devices—no need to change them one by one. Also, if you have children at home, remember to check if the parental controls have restricted internet access on this device. Some routers have child internet mode that directly disconnects the network of specific devices, acting exactly like disconnecting the internet. I previously mentioned this pitfall when I wrote about guest network and internet time management .

Step 5: Android shows "Network Limited," but the actual network is connected

This step is specifically written for Android users and is the hardest to detect, because it's a 'fake fault.' The manifestation is: the WiFi icon has an exclamation mark, the system prompts 'Connected, but cannot access the network,' but when you open the browser, you find the webpage actually opens up.

This isn't a problem with your network; it's just that Android's network detection mechanism is causing false positives. After connecting to WiFi, Android secretly visits a detection website (generate_204) to check if the network is working. In domestic environments, accessing Google's detection servers often fails, so the system puts an exclamation mark on the WiFi. It looks uncomfortable, but in reality, it doesn't affect anything.

want to get rid of this exclamation mark, either turn off IPv6 in the router's background (many Android phones use IPv6 for detection, but domestic IPv6 routing is incorrect and falsely alarms), or set private DNS to dns.alidns.com on your phone. After upgrading the system on my Redmi Note 12, the exclamation mark lit up for a week, but after turning off the router's IPv6, it disappeared. Of course, if your router's IPv6 is working fine, you can just ignore it—it's just a hint. OCD needs to be treated.

really had no choice, so I followed this order to do the last three moves

you've completed all five steps above and still don't have a net, then only three tricks remain. Let's do them in order:

• both the optical modem and router are powered off. Wait 30 seconds to turn on the optical modem, then wait until the light is stable before turning on the router. Don't use the "Restart" button in the background to cut off power directly. Many strange cache issues require power outages to clear the issue.
• log in to the router backend to restore factory and reset your broadband account and password. Be sure to note your broadband account password before factory reset; you can find it by calling your carrier's customer service.
• call the carrier (Telecom 10000, China Unicom 10010, China Mobile 10086) and have the technician come to your door. When reporting for repair, they say you've already tested the 'optical modem direct computer dial-up,' so customer service won't use tricks to brush you off—they'll just send orders faster.

Finally, here's a simple but real scenario: for renters, if the landlord's broadband is linked to the MAC address of the original router, the entire network will be cut off when you replace the router. The solution is to find the "MAC Address Clone" function in the backend of the new router to change the WAN port MAC to the old router's. I helped a colleague look into this pit all afternoon and finally found out it was just about this switch.

summarize the troubleshooting sequence: first distinguish between one device and the whole system → check the lights and WAN port → check if the phone's IP is 169.254 → change DNS → detect Android's fake exclamation marks. Remember this sequence—next time your home goes offline, you'll be the most reliable person in the room.