Is it down? Website down checker
Find out if a website is down for everyone or just for you. We open the address from each of our check regions and show what every one of them got back.
网站宕机检测
检测网站是所有人都打不开，还是只有你打不开。我们会从每个检测区域访问这个地址，并显示每个区域得到的结果。
How to read the result
- Up: At least one region got a 2xx response. If the site does not load for you, the problem is likely on your side: your network, a stale DNS cache, a VPN or a browser extension.
- Responding with an error: The server answered, but with a 4xx or 5xx status. A 5xx usually means the application or a server behind a proxy is failing; a 403 or 429 can also mean the site blocks automated checks.
- Down: No region got any answer: the connection was refused, timed out after 10 seconds or failed during TLS. A name with no A or AAAA record is also down.
Common reasons a site goes down
- A deploy that broke the application or its configuration.
- The server, container or database ran out of memory, disk or connections.
- An expired TLS certificate, which browsers refuse to open.
- A DNS change, an expired domain or a record that points to an old server.
- An outage at the hosting provider, CDN or another service the site needs.
Know before your users do
A one-off check tells you about now. An OpenUptime monitor checks your site every few minutes, or as often as every 30 seconds on the Team plan, can check from several regions and count a failure only when most of them fail, and can publish the outage on a status page.
Questions
How do I know if a website is down for everyone or just me?
Check it from somewhere other than your own network. This tool opens the address from each of our check regions. If they all get a good answer, the site is up and the problem is between you and it: your connection, DNS cache, VPN, firewall or browser.
What counts as up?
A response with a 2xx status after following up to five redirects. A 4xx or 5xx status means the server answered but with an error, and no answer at all within 10 seconds means it is down from that region.
Why does the checker say a site is down when it opens in my browser?
Some sites block automated requests or requests from data centers, answering 403 or 429, or only respond in certain countries. Others are only reachable inside a company network. The result shows the exact status or error each region got.
What should I do when my own site is down?
Check whether the name still resolves (try the DNS lookup), whether the certificate is valid (try the SSL checker), and whether your host or CDN reports an incident. Then look at your server logs and recent deploys, and tell your users on a status page.
Does this keep watching the site?
No, it checks once when you ask. To be told the moment a site goes down, add it as a monitor: OpenUptime checks it on a schedule, from one or several regions, and alerts you by email, Slack, webhook and other channels.
如何理解结果
- 正常: 至少有一个区域得到了 2xx 响应。如果你这里打不开，问题多半在你这一侧：你的网络、过期的 DNS 缓存、VPN 或浏览器插件。
- 返回错误: 服务器有响应，但状态码是 4xx 或 5xx。5xx 通常表示应用或代理后面的服务器出了故障；403 或 429 也可能是网站拦截了自动化检测。
- 宕机: 所有区域都没有得到任何响应：连接被拒绝、10 秒内超时或 TLS 握手失败。没有 A 或 AAAA 记录的域名也算宕机。
网站宕机的常见原因
- 一次发布破坏了应用或它的配置。
- 服务器、容器或数据库的内存、磁盘或连接数耗尽。
- TLS 证书过期，浏览器拒绝打开。
- DNS 变更、域名过期，或记录仍指向旧服务器。
- 主机商、CDN 或网站依赖的其他服务发生故障。
比用户更早知道
单次检测只能告诉你此刻的情况。OpenUptime 的监控每隔几分钟检查一次你的网站（Team 套餐最快每 30 秒一次），可以从多个区域检查，只有多数区域都失败时才算一次故障，还可以把故障发布到状态页上。
常见问题
怎么判断网站是所有人都打不开，还是只有我打不开？
从你自己的网络以外的地方访问它。这个工具会从我们的每个检测区域打开这个地址。如果它们都得到了正常响应，说明网站是好的，问题出在你和网站之间：你的网络、DNS 缓存、VPN、防火墙或浏览器。
什么情况算正常？
在最多跟随五次重定向之后，得到 2xx 状态码的响应。4xx 或 5xx 表示服务器有响应但返回了错误；10 秒内完全没有响应，则表示从该区域看它是宕机的。
为什么检测说网站宕机了，但我的浏览器能打开？
有些网站会拦截自动化请求或来自数据中心的请求，返回 403 或 429，或只在某些国家可以访问；还有的只在公司内网才能访问。结果中会显示每个区域得到的具体状态码或错误。
我自己的网站宕机了怎么办？
先看域名是否还能解析（用 DNS 查询），证书是否有效（用 SSL 证书检测），以及你的主机或 CDN 是否公布了故障。然后查看服务器日志和最近的发布，并通过状态页告知用户。
这个工具会持续监控网站吗？
不会，它只在你点击时检查一次。要在网站宕机时第一时间收到通知，请把它添加为监控：OpenUptime 会按计划从一个或多个区域检查它，并通过邮件、Slack、Webhook 等渠道提醒你。