--- title: "Cold Email Foundation | FirstSales Masterclass" description: "Build a rock-solid cold email foundation. Learn domain setup, DNS records, and infrastructure that scales without hurting deliverability." canonical: "https://firstsales.io/masterclass/building-your-foundation/" --- Cold Email Masterclass Chapter 3 of 15 20% Table of Contents [Why Cold Email Still Works in 2026](/masterclass/why-cold-email-still-works/)[The Cold Email Mindset Shift](/masterclass/cold-email-mindset-shift/)[3Building Your Foundation](/masterclass/building-your-foundation/)[4Inbox Warm-Up Strategy](/masterclass/inbox-warm-up-strategy/)[5List Building & Research](/masterclass/list-building-research/)[6Writing Cold Emails That Get Replies](/masterclass/writing-cold-emails-get-replies/)[7Personalization at Scale](/masterclass/personalization-at-scale/)[8Follow-Up Sequences That Convert](/masterclass/follow-up-sequences-convert/)[9Cold Email Deliverability Mastery](/masterclass/cold-email-deliverability-mastery/)[10Multi-Channel Outreach](/masterclass/multi-channel-outreach/)[11AI-Powered Cold Email in 2026](/masterclass/ai-powered-cold-email-2026/)[12Measuring Cold Email Performance](/masterclass/measuring-cold-email-performance/)[13Compliance and Legal Requirements](/masterclass/compliance-legal-requirements/)[14Scaling Your Cold Email Operation](/masterclass/scaling-cold-email-operation/)[15Advanced Strategies Most People Never Try](/masterclass/advanced-strategies-never-try/) Your progress Completed 20% 3 of 15 chapters 3 Chapter 3 Cold Email Masterclass # Building Your Foundation This chapter is not exciting. It is the **most important chapter** in this entire cold email masterclass. ## Deliverability Is Everything Deliverability is the foundation of everything. If your emails do not reach the inbox, your copywriting skills, your personalization, and your follow-up sequences are worthless. The global average inbox placement rate sits at **83.1%**. That means roughly 17% of all emails never reach the primary inbox. For cold email specifically, that number is worse because cold senders face higher scrutiny from spam filters. Here is what you need to set up before sending a single cold email. --- ## Domain Authentication: SPF, DKIM, and DMARC These three protocols prove to email providers that you are who you say you are. Without them, your emails look suspicious. ### SPF (Sender Policy Framework) SPF tells receiving servers which IP addresses can send email on behalf of your domain. Think of it as a guest list. If the sending server is not on the list, the email gets flagged. **How to set it up:** Add a TXT record to your DNS that lists your authorized sending services. v=spf1 include:\_spf.google.com include:youremailservice.com \~all ### DKIM (DomainKeys Identified Mail) DKIM adds a digital signature to each email you send. The receiving server checks this signature against a public key in your DNS. If the signature matches, the email passes verification. **How to set it up:** Your email service provider generates a DKIM key pair. You add the public key as a TXT record in your DNS. ### DMARC (Domain-based Message Authentication, Reporting, and Conformance) DMARC ties SPF and DKIM together. It tells receiving servers what to do with emails that fail authentication checks. **How to set it up:** Add a TXT record to your DNS. v=DMARC1; p=reject; rua=mailto:dmarc@yourdomain.com 2026 Standard In 2026, setting your DMARC policy to p=reject is becoming the standard. This tells receiving servers to reject any email that fails SPF or DKIM checks. It protects your domain from spoofing and signals that you take authentication seriously. --- ## Protocol Comparison Protocol What It Does Impact on Deliverability SPF Authorizes sending servers ✓ Prevents spoofing from unauthorized IPs DKIM Signs emails cryptographically ✓ Proves email was not altered in transit DMARC Enforces SPF + DKIM policies ✓ Tells providers how to handle failures No Auth Nothing ✗ Emails land in spam or get rejected --- ## Buying Secondary Domains Never send cold email from your primary business domain. **Never.** If your company is acme.com, buy domains like getacme.com, acmehq.com, tryacme.com, or acme.io for cold outreach. If a cold email domain gets blacklisted, your primary domain stays clean. Your marketing emails, transactional emails, and customer communications remain unaffected. Buy 3-5 secondary domains. Set up separate Google Workspace or Microsoft 365 accounts on each. Authenticate SPF, DKIM, and DMARC on every single one. Cost: roughly $12 per domain per year plus $6-$7 per inbox per month on Google Workspace. A small price compared to having your main domain flagged as spam. --- ## Email Provider Selection Google Workspace and Microsoft 365 are the two dominant choices for cold email. Google WorkspaceHas the best deliverability for cold email in 2026\. Google knows its own spam filters, and emails from Google Workspace tend to perform better in Gmail inboxes, which represent roughly 30% of business email. Microsoft 365Works well for reaching Outlook and corporate inboxes. Many enterprise companies run on Microsoft infrastructure, and emails from Microsoft 365 accounts sometimes get preferential treatment in those environments. Strategy The smart move: use both. Set up inboxes on Google Workspace and Microsoft 365\. Rotate between them to spread volume and reduce risk. --- ## Inbox Limits and Safe Sending Each inbox has a safe daily sending limit for cold email: Phase Cold Email Sends Time Period New inboxes 5-10 emails per day First 2 weeks Warming phase 15-25 emails per day Weeks 2-4 Fully warmed 35-50 emails per day maximum Month 2+ These numbers feel low. That is the point. Cold email in 2026 is a precision game, not a volume game. If you need to send 500 emails per day, you need 10-15 warmed inboxes. Not one inbox pushing 500 sends. Firstsales.io Advantage Tools like Firstsales.io let you connect unlimited email accounts and rotate sends automatically. This spreads volume across inboxes so no single account gets flagged for unusual activity. --- Key Takeaway Deliverability is the foundation. Skip authentication and proper setup, and nothing else matters. Set up SPF, DKIM, and DMARC. Use secondary domains. Respect inbox limits. Your future self will thank you. [Previous](/masterclass/cold-email-mindset-shift/)[Next chapter](/masterclass/inbox-warm-up-strategy/) AI SDR · works 24/7 ## You learned it. Now automate the whole loop. FirstSales is the AI SDR that runs the entire cold email loop on autopilot: finds leads, writes every email, follows up, and books the meeting. From $29/mo. Set up in 8 minutes. * Finds leads by scraping the web * Writes and personalizes every email * Follows up automatically * Books meetings to your calendar * 87% lands in the primary inbox [Get started for $1](https://app.firstsales.io)[See pricing](/pricing/) $1 for 3 days · Cancel anytime · Live in 8 minutes Continue Learning ## Related Masterclass Chapters Explore more chapters from the Cold Email Masterclass. [Chapter 1Why Cold Email Still Works in 20268 min](/masterclass/why-cold-email-still-works/)[Chapter 2The Cold Email Mindset Shift7 min](/masterclass/cold-email-mindset-shift/)[Chapter 4Inbox Warm-Up Strategy7 min](/masterclass/inbox-warm-up-strategy/)[Chapter 5List Building & Research9 min](/masterclass/list-building-research/)[Chapter 6Writing Cold Emails That Get Replies8 min](/masterclass/writing-cold-emails-get-replies/)[Chapter 7Personalization at Scale7 min](/masterclass/personalization-at-scale/) [View All Chapters ](/masterclass/) ## FAQs Your questions answered Can't find what you're looking for? Contact our [customer support team](mailto:support@firstsales.io) ### General ### ### ### ### Deliverability ### ### Can't find what you're looking for? Contact our [customer support team](mailto:support@firstsales.io)