SPF record checker
SPF checker: read a domain’s SPF record、list its mechanisms、10. count the DNS lookups against the limit
Queries go〜Cloudflare’s public DNS over HTTPS service when you press the button. Up〜15 queries are made〜follow include records.
SPF record checkerについて
SPF checker: read a domain’s SPF record、list its mechanisms、10. count the DNS lookups against the limit
SmartCalcyの「データとネットワーク」セクションの一部です。アカウント不要でブラウザ上で動作し、お使いの通貨と単位（ページ上部で変更可）を使います。結果は参考用の目安なので、頼る前に公的な情報をご確認ください。
SPF record checkerの使い方
何を計算するか、いつ使うか
Reads a domain’s SPF record、servers allowed〜send email the list個でit,、checks it個でcommon faults: more than one record、a missing “all” policy,、more than 10 DNS lookups, which makes SPF fail. It follows include records〜count the lookups.
使い方の手順
- Enter the domain,個で例 例.com.
- Press “Check SPF”.
- Read the verdictと10. DNS lookups used out the number
- Review the mechanisms listとany warnings.
各入力項目の意味
- Domain 名前 – the sender’s address.のThe domain used
結果の読み方
- Verdict – Looks valid,またはNeeds attention when a problemはfound.です
- Policy – What happens〜mail from servers that are not listed: hard fail, soft fail, neutralまたはallow.
- DNS lookups – Lookups needed by include、a, mx, ptr, exists、10. redirect terms, compared with the limit
- Mechanisms – the record, with included records indented beneath their parent.のEvery 期間
計算式
The recordはthe TXT value starting v=spf1. Each includeです、a, mx, ptr, existsまたはredirect term costs one DNS lookup,、included records add their own. ip4とip6 termsと“all” cost none. The RFC limitは10 lookups.です
計算例
v=spf1 include:_spf.example.net a mx -all uses three lookups個でits own terms plus those inside the included record,と-all, so unlisted servers are rejected.のends
前提と限界
- 適用 most 15 queries are made while following includes,とnesting stops after 5 levels.
- A domain may need a record only個でmail it sends. Domains that send いいえ mail should publish v=spf1 -all.
- The check does not test whether a particular server would pass.
よくある間違い
- Publishing two SPF records. Only oneはallowed, so merge them into one.です
- Ending with +all, which lets anyone send as your domain.
- Adding every email service as an includeとpassing 10 lookups, which 回転 SPF into a permanent error.
よくある質問
WhatはSPF?です
Sender Policy Frameworkはa DNS record that lists the servers allowed〜send emailです個でa domain.
Whatはthe difference between -allですと~all?
-all asks receivers〜reject unlisted senders. ~all asks them〜accept but mark the mail as suspicious.
Whyは10 lookups? there a limitです
DNS queries. Going over it makes SPF return a permanent error. It stops a record 開始 forcing receivers into long chains
Is SPF enough〜stop spoofing?
いいえ. Use it with DKIMとDMARC.
Does this tool send email?
いいえ. It only reads DNS records.