DNS record monitoring
A wrong DNS record breaks a site or mail as surely as a crashed server, and cached answers hide it for hours. Check the record itself.
What each check does
- Looks up one record type for a name through Cloudflare's public resolver.
- Optionally compares the answer with the value you expect, exactly or as "contains".
When it alerts
- The name does not exist or has no record of that type.
- The answer no longer matches the expected value, for example an A record that moved or an MX that was replaced.
Example
example.comGood to know
- Record types: A, AAAA, CNAME, MX, TXT and NS.
- Use "contains" for TXT records such as SPF, where other values share the same name.
On every monitor
- Alerts by email, Slack, Discord, Teams, Telegram, PagerDuty, webhooks, Lark, ntfy and the mobile app.
- Recovery thresholds, so an incident closes only after the service has answered several times in a row.
- Dependencies: a monitor that depends on another stays quiet while that one is down.
- Maintenance windows, incident history and public status pages built from the same monitors.
Try it on the Free plan
The Free plan includes 3 monitors checked every 5 minutes, with every alert channel. No card needed.
Questions
What should I check with a DNS monitor?
The A or CNAME of your main site, the MX records of your mail domain, your SPF record, and the NS records, which change when someone moves the domain to other name servers.
Does it check my authoritative servers directly?
No. It asks a public resolver, so it sees what your visitors see, including what that resolver has cached.
DNS 记录监控
一条错误的 DNS 记录和服务器崩溃一样会让网站或邮件失效，而缓存会把问题掩盖好几个小时。直接检查记录本身。
每次检查做什么
- 通过 Cloudflare 公共解析器查询一个名称的某种记录。
- 可以把结果和你预期的值比较，精确匹配或“包含”匹配。
什么时候告警
- 名称不存在，或没有这种类型的记录。
- 结果不再匹配预期值，例如 A 记录指向了别处，或 MX 被替换了。
示例
example.com使用说明
- 记录类型：A、AAAA、CNAME、MX、TXT 和 NS。
- SPF 等 TXT 记录和其他值共用同一个名称，这时用“包含”匹配。
所有监控通用
- 通过邮件、Slack、Discord、Teams、Telegram、PagerDuty、Webhook、飞书、ntfy 和手机 App 告警。
- 可设置恢复阈值，服务连续多次正常后故障才结束。
- 依赖关系：依赖另一个监控的监控，在被依赖方宕机期间不会告警。
- 维护窗口、故障历史，以及由同一组监控生成的公开状态页。
常见问题
DNS 监控应该检查什么？
主站的 A 或 CNAME 记录、邮件域名的 MX 记录、SPF 记录，以及 NS 记录——有人把域名迁到别的域名服务器时，NS 会变化。
它会直接查询我的权威服务器吗？
不会。它查询的是公共解析器，因此看到的和访客看到的一样，也包括该解析器的缓存。