SPF Analyzer

SPF is a method to prevent email sender address forgery.


Enter a domain to view and analyze its SPF record:


"250ok has built a best-of-breed platform that addresses the concerns of today's data-driven marketers."


Len Shneyder
VP of Industry Relations at SendGrid

Need assistance with SPF? See how 250ok can help.



More Free Tools

Blacklist Checker

Instantly check an IP or domain against major email blacklists including Spamhaus, SURBL, SORBS, and more.


Use Blacklist Checker


CIDR to IP Range

Enter a CIDR notation to instantly convert it to an IP range.


Use CIDR to IP Range

SPF Analyzer

SPF is a method to prevent email sender address forgery. Enter your domain to analyze its SPF record.


Use SPF Analyzer


IP Range to CIDR

Enter a IP range to instantly convert it to a CIDR notation.


Use IP Range to CIDR

DMARC Wizard

Enter your domain to analyze your DMARC record or create a DMARC policy for your domain.


Use DMARC Wizard


DNS Lookup

Perform a DNS lookup against multiple widely used nameservers around the world.


Use DNS Lookup

Resources for #SeriousSenders


Deliverability 101: Brazil’s new privacy legislation is similar to the GDPR.

In August 2018, the Brazilian parliament passed Law No. 13,709, a new privacy law known as the Brazilian General Data Protection Law (GDPL), updating and amending the existing “Brazilian Internet Law” of 2014. This is another example of major global economies updating outdated privacy legislation to provide more consumer-favored legislation, similar to the GDPR. There […]

Poorly designed emails could cost you millions of dollars. But what does that really mean?

We partnered with the smart folks at Lab42 to research what people really think about marketing email. Do they like how they look on their preferred device? Do they prioritize the same design elements you do? If you’re not aligned with your recipients, you could end up sending unwanted, unsatisfying email. You know what that […]

How to properly use third-party data to grow your list.

There seems to be a lot of confusion and bad advice in the marketplace about growing email lists with the aid of third-party data sources. Some advice encourages you to rent or purchase data, then run it through an email validation service before your distribution to remove as much of the (potentially) bad stuff as […]




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