Tool

MxToolbox SuperTool

MxToolbox Freemium Beginner

A single search bar to look up your SPF, DKIM, DMARC, MX, and PTR records, plus a blacklist check across dozens of blocklists. It is the fastest way to confirm your DNS records actually propagated correctly and match what your ESP told you to set, before you assume the problem is something else.

  • Checks SPF, DKIM, DMARC, MX, and reverse DNS from one search box
  • Flags common SPF mistakes like exceeding the 10 DNS lookup limit
  • Scans your sending domain and IP against 100-plus blacklists
Open on mxtoolbox.com ↗

The question it answers

  1. My cold emails keep landing in spam. How do I fix deliverability?

Read with it

  1. A tactical follow-on covering the channels and motions top B2B startups scale after the first ten. Grounds distribution... Lenny's Newsletter Article · ~15 min read How to win your first 10 B2B customers Lenny Rachitsky
  2. This is the book most modern cold outbound advice quietly borrows from, so reading the source is worth it. Its "Cold Calling... Amazon Book · ~208 pages Predictable Revenue: Turn Your Business Into a Sales Machine with the $100 Million Best Practices of Salesforce.com Aaron Ross and Marylou Tyler
  3. An Indian founder story where the early demand test was manual, cold emails and direct outreach to find the first customers... Prime Venture Partners Podcast Podcast · ~50 min How Khadim Batti Built Whatfix Into a Global SaaS Leader Prime Venture Partners
  4. Once you have a list of people to reach cold, this shows you how to write emails they actually answer. Seven concrete... Y Combinator Startup Library Video · ~33 min How to Convert Customers With Cold Emails Aaron Epstein
  5. If your warm interest is coming from larger companies that never sign, this Indian podcast episode digs into why enterprise... The Neon Show Podcast How Startups Can Sell to Big Companies (The Neon Show) Siddhartha Ahluwalia
  6. This is Google's own rulebook for what gets an email into Gmail instead of spam: SPF or DKIM for every sender, SPF, DKIM, and... Google (Gmail/Workspace support) Article Email sender guidelines Google (Gmail/Workspace support)
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