This is a list of URLs commonly used for checking network connectivity, and for detecting the existence of “Captive Portals“.
| Provider | URL | China? | HTTP | HTTPS | IPv6 |
|---|---|---|---|---|---|
www.gstatic.com/generate_204 | ⚠ | 204 | 204 | ✔ | |
www.google-analytics.com/generate_204 | ⚠ | 204 | 204 | ✔ | |
www.google.com/generate_204 | ❌ | 204 | 204 | ✔ | |
connectivitycheck.gstatic.com/generate_204 | ⚠ | 204 | 204 | ✔ | |
| Apple | captive.apple.com | ✔ | 200 | 200 | ✔ |
| Apple | www.apple.com/library/test/success.html | ✔ | 200 | 200 | ⚠* |
| Microsoft | www.msftconnecttest.com/connecttest.txt | ✔ | 200 | ❌ | ❌ |
| Microsoft | edge.microsoft.com/captiveportal/generate_204 | ✔ | 204 | 400 | ✔ |
| Cloudflare | cp.cloudflare.com | ⚠ | 204 | 204 | ✔ |
| Firefox | detectportal.firefox.com/success.txt | ⚠ | 200 | 200 | ✔ |
| Qualcomm (China) | www.qualcomm.cn/generate_204 | ✔ | 204 | 301 | ✔ |
| Xiaomi | connect.rom.miui.com/generate_204 | ✔ | 204 | 204 | ❌ |
| Huawei | connectivitycheck.platform.hicloud.com/generate_204 | ✔ | 204 | 204 | ❌ |
| Vivo | wifi.vivo.com.cn/generate_204 | ✔ | 204 | 204 | ❌ |
| USTC | 204.ustclug.org | ✔ | 204 | 204 | ✔ |
About the “China?” column:
- ✔ – Chinese company (entity) or company with Chinese presence. Should be stable.
- ⚠ – Currently accessible (or partially accessible) from China, but could be blocked at any moment.
- ❌ – Currently blocked in China.
* Special note for www.apple.com: As of now, it doesn’t resolve to an IPv6 address when queried from China.
Sources:
