--- title: "What is an SPF Checker MxToolbox, and How Does it Validates SPF Records? | DuoCircle" image: "https://www.duocircle.com/images/og-default.png" canonical: "https://www.duocircle.com/resources/what-is-an-spf-checker-mxtoolbox-and-how-does-it-validates-spf-records/" --- DuoCircle # What is an SPF Checker MxToolbox, and How Does it Validates SPF Records? [ Talk to an Expert → ](/contact/) [ See what we make ](/products/) ## What is an SPF Checker MxToolbox, and How Does it Validates SPF Records? ## What is an SPF Checker MxToolbox, and How Does it Validates SPF Records? [Fix Your SPF Errors Now](/content/spf-permerror) ###### [EMAIL SECURITY SERVICES](/) ###### [PLANS AND PRICING](/email/outbound-smtp#pricingarea) ###### [SPF RECORDS](/email/spf-record-check) ### Preface SPF checker MxToolbox is a diagnostic tool that looks up SPF records for errors and **ensures their validity**. SPF or Sender Policy Framework allows domain administrators to create and publish a list of servers permitted to send emails from a particular domain. It protects your domain from [spamming](https://gizmodo.com/chatgpt-ai-gmail-spam-personalized-inbox-flood-1850363854) and [phishing attacks](/resources/how-does-a-phishing-attack-work) attempted in your company’s name. To use the MxToolbox SPF checker, you just need to enter your domain name in the given space, and you’ll receive a full-fledged report in just a few seconds. You can remediate the issues and update your SPF record to stay abreast of cybercriminals. ![email security](https://media.mailhop.org/duocircle/images/2019/02/email-phishing-protection.png) ### How MxToolbox SPF Record Checker Validates Your Record? MxToolbox SPF record checker will validate SPF records on the: - **SPF record existence**: The [SPF checker](/dkim-and-spf-checkers-how-do-they-work) MxToolbox requires an SPF record to start the validation process. - **Multiple SPF records in DNS**: You can’t have more than one SPF record in DNS for each version. - **Maximum lookups**: There’s a limit of a maximum of [10 DNS lookups](/content/spf-too-many-dns-lookups). If you exceed the limit, your email messages will fail inspections. - **_Ptr_** **mechanism**: The _ptr_ mechanism is slow and unreliable; thus, its use is discouraged, and it’s a deprecated mechanism. - **Unknown parts found**: Content not specified by SPF is in use. - **+All mechanism used**: The use of this tag is discouraged as it allows anyone to send messages from your domain. - **Record termination missing**: The SPF checker MxToolbox checks if your record has either an ‘all’ mechanism or a ‘redirect’ modifier. - **Multiple fall-back scenarios**: There shouldn’t be more than one SPF fall-back scenario. - **DNS type ‘SPF’ used**: Your SPF record should be in the ‘TXT’ format as the ‘SPF’ format is obsolete. - **Uppercase SPF**: It isn’t mandatory to use lowercase characters, however, it’s considered a good practice. ![email security](https://media.mailhop.org/duocircle/images/2021/09/azure-tenant-migration.png) ## Ready to talk? Same-day response from someone technical. We tell you yes or no quickly. If yes, we get to work. [Talk to an Expert→](/contact/)[See what we make](/products/) ```json {"@context":"https://schema.org","@type":"Organization","name":"DuoCircle LLC","url":"https://www.duocircle.com","logo":{"@type":"ImageObject","url":"https://www.duocircle.com/images/duocircle-logo.png"},"description":"DuoCircle is a portfolio of specialized email products covering protection, authentication, delivery, and routing. We deliver about 90% of category-leader capability at roughly half the price, backed by experts who own the outcome. 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