SPF record checker
SPF checker: read a domain’s SPF record、list its mechanisms、count the DNS lookups against the limit 10.
Queries go 至 Cloudflare’s public DNS over HTTPS service when you press the button. Up 至 15 queries are made 至 follow include records.
关于SPF record checker
SPF checker: read a domain’s SPF record、list its mechanisms、count the DNS lookups against the limit 10.
属于 SmartCalcy“数据与网络”板块。它在你的浏览器中运行，无需账号，使用你自己的货币和单位（可在页面顶部更改），所给结果仅为估算、仅供参考，因此在依赖结果之前请查阅官方指引。
如何使用SPF record checker
它计算什么，何时使用
Reads a domain’s SPF record、the list servers allowed 至 send email件it,、checks it件common faults: more than one record、a missing “all” policy,、more than 10 DNS lookups, which makes SPF fail. It follows include records 至 count the lookups.
使用步骤
- Enter the domain,件示例 示例.com.
- Press “Check SPF”.
- Read the verdict 和 the number DNS lookups used out 10.
- Review the mechanisms list 和 any warnings.
各输入项的含义
- Domain 名称 – the sender’s address. 的 The domain used
如何阅读结果
- Verdict – Looks valid, 或 Needs attention when a problem 是 found.
- Policy – What happens 至 mail from servers that are not listed: hard fail, soft fail, neutral 或 allow.
- DNS lookups – Lookups needed by include、a, mx, ptr, exists、redirect terms, compared with the limit 10.
- Mechanisms – the record, with included records indented beneath their parent. 的 Every 期限
公式
The record 是 the TXT value starting v=spf1. Each include、a, mx, ptr, exists 或 redirect term costs one DNS lookup,、included records add their own. ip4 和 ip6 terms 和 “all” cost none. The RFC limit 是 10 lookups.
计算示例
v=spf1 include:_spf.示例.net a mx -all uses three lookups件its own terms plus those inside the included record, 和 -all, so unlisted servers are rejected. 的 ends
假设与局限
- 以 most 15 queries are made while following includes, 和 nesting stops after 5 levels.
- A domain may need a record only件mail it sends. Domains that send 否 mail should publish v=spf1 -all.
- The check does not test whether a particular server would pass.
常见错误
- Publishing two SPF records. Only one 是 allowed, so merge them into one.
- Ending with +all, which lets anyone send as your domain.
- Adding every email service as an include 和 passing 10 lookups, which 圈 SPF into a permanent error.
常见问题
What 是 SPF?
Sender Policy Framework 是 a DNS record that lists the servers allowed 至 send email件a domain.
What 是 the difference between -all 和 ~all?
-all asks receivers 至 reject unlisted senders. ~all asks them 至 accept but mark the mail as suspicious.
Why 是 there a limit 10 lookups?
It stops a record 从 forcing receivers into long chains DNS queries. Going over it makes SPF return a permanent error.
Is SPF enough 至 stop spoofing?
否. Use it with DKIM 和 DMARC.
Does this tool send email?
否. It only reads DNS records.