How to Configure SPF, DKIM, and DMARC for Email Deliverability

If your emails are constantly landing in the spam folder, chances are your domain authentication isn’t properly set up. In 2025, email providers like Gmail, Outlook, and Yahoo rely heavily on SPF, DKIM, and DMARC records to decide if your message is genuine or suspicious.

This guide will walk you through exactly how to configure SPF, DKIM, and DMARC, even if you’re not a technical expert.

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🔍 What Are SPF, DKIM, and DMARC?

Protocol	Purpose	Where It’s Set
SPF (Sender Policy Framework)	Verifies who’s allowed to send email on your domain’s behalf	DNS TXT record
DKIM (DomainKeys Identified Mail)	Adds a digital signature to email headers	DNS TXT record & email server
DMARC (Domain-based Message Authentication, Reporting & Conformance)	Tells mailbox providers what to do if SPF/DKIM fail	DNS TXT record

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✅ Step 1: Set Up SPF Record

SPF allows only authorized servers to send emails using your domain.

How to Set Up:

1. Login to your domain DNS panel (GoDaddy, Cloudflare, Namecheap, etc.).
2. Create or edit a TXT record.
3. Enter the SPF syntax:

txtCopyEditv=spf1 include:your-email-provider.com ~all

✅ Example for Inboos:

txtCopyEditv=spf1 include:smtp.inboos.com ~all

🔹 ~all = Soft fail (mark suspicious, don’t block)
🔹 -all = Hard fail (reject unauthorized sources)
🔹 ?all = Neutral (no policy)

Tips:

• You can only have one SPF record per domain.
• Combine services if using more than one provider.

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✅ Step 2: Configure DKIM Record

DKIM signs each outgoing message with a private key and lets receivers verify it with a public key.

How to Set Up:

1. Inside your email provider or SMTP platform (like Inboos), generate DKIM keys.
2. You’ll receive:
   • Selector (e.g., default)
   • Public Key (long string)
3. Add a TXT record to your domain:

Type	Host/Name	Value
TXT	default._domainkey.yourdomain.com	v=DKIM1; k=rsa; p=MIGf...

✅ Example:

txtCopyEditv=DKIM1; k=rsa; p=MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDh...

Tips:

• TTL can be left default (usually 3600 seconds).
• Some providers offer auto DKIM configuration via CNAME instead of TXT.

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✅ Step 3: Publish DMARC Record

DMARC tells receivers how to handle unauthenticated mail and lets you receive reports.

How to Set Up:

1. Add a new TXT record in your DNS settings.
2. Use the following format:

txtCopyEditv=DMARC1; p=quarantine; rua=mailto:reports@yourdomain.com; ruf=mailto:forensics@yourdomain.com; fo=1

✅ Breakdown:

• p= = policy: none, quarantine, or reject
• rua= = email for aggregate reports
• ruf= = email for forensic reports
• fo=1 = send a report if either SPF or DKIM fails

Example:

Type	Name	Value
TXT	_dmarc.yourdomain.com	v=DMARC1; p=quarantine; rua=mailto:reports@yourdomain.com; fo=1

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📊 Table: Sample DNS Setup for Inboos Users

Record Type	Host	Value	Purpose
SPF	@	v=spf1 include:smtp.inboos.com ~all	Allow Inboos to send
DKIM	inboos._domainkey	v=DKIM1; k=rsa; p=MIGf...	Authenticate Inboos emails
DMARC	_dmarc	v=DMARC1; p=quarantine; rua=mailto:you@domain.com	Protect domain reputation

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🚨 Common Mistakes to Avoid

Mistake	Problem	Fix
Multiple SPF records	Invalidates all SPF	Combine into one record
Missing DKIM record	Fails authentication	Enable in sending platform
No DMARC policy	No protection	Set p=none to start
Wrong syntax	DNS fails	Use online validation tools

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🛠 Recommended Tools

• MXToolbox – DNS record checker
• Google Postmaster Tools – Monitor deliverability
• DMARC Analyzer – Visualize DMARC reports
• Inboos Dashboard – Built-in record tester & alerts

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💼 Why You Need This Setup in 2025

Mailbox providers now require domain authentication. Without it, your emails:

• Will land in spam
• Get blocked silently
• Damage your IP/domain reputation
• Reduce open and click rates

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🚀 Need Help? Let Inboos Do It for You

At Inboos, we don’t just provide an email platform — we ensure every email you send is fully authenticated and optimized for inbox delivery.

🔹 Free SPF/DKIM/DMARC Setup
🔹 Real-time DNS status in dashboard
🔹 Auto-warmup and deliverability boosting
🔹 AI-powered domain rotation + IP control
🔹 Built for mass emailing, cold outreach, and transactional APIs

👉 Visit Inboos.com to get started — and stop guessing if your emails land.