Setting Up a Custom Domain

Using a custom domain dramatically improves email deliverability and creates a professional sender identity. This guide walks you through the setup process.

Why Use a Custom Domain?

Benefits:

• ✅ Better deliverability - Own your sender reputation
• ✅ Professional branding - Emails from your@yourdomain.com
• ✅ Trust signals - Recipients recognize your brand
• ✅ Full control - Not affected by shared sending infrastructure
• ✅ Analytics - Track domain-specific metrics

vs. Shared sending domain:

• ❌ Shared reputation with other senders
• ❌ Generic sender address
• ❌ Lower trust from recipients
• ❌ Less control over deliverability

Prerequisites

Before starting, you need:

• A registered domain (e.g., yourdomain.com)
• Access to your domain's DNS settings
• Admin access to Penna dashboard

Step 1: Add Domain in Penna

1. Log into your Penna dashboard
2. Go to Settings → Domain
3. Click "Add Custom Domain"
4. Enter your domain (e.g., yourdomain.com)
5. Click "Add Domain"

Penna will generate the DNS records you need to add.

Step 2: Configure DNS Records

Important: All DNS records are generated specifically for your account in your Penna dashboard. Always copy the exact values shown there - don't use examples from this guide.

How to Find Your DNS Records

1. Go to Settings → Domain → DNS Records in your Penna dashboard
2. You'll see all required records with exact values
3. Copy each record exactly as shown
4. Add them to your domain's DNS provider

Required DNS Records

Your dashboard will show these records. Here's what each one does:

SPF Record

• Purpose: Authorizes Penna (via Amazon SES) to send emails from your domain
• Copy from dashboard: The exact SPF value including Amazon SES configuration
• Note: If you already have an SPF record, your dashboard will show how to merge them

DKIM Record

• Purpose: Digitally signs your emails to prove authenticity
• Copy from dashboard: The full DKIM value (it's long and unique to your account)
• Note: The record name will include a specific selector

DMARC Record

• Purpose: Tells email servers what to do if SPF/DKIM checks fail
• Copy from dashboard: Your DMARC policy configuration
• Note: Start with monitoring mode (p=none), then move to p=quarantine after 2-4 weeks

Recommended approach:

1. Start with p=none to monitor
2. After 2-4 weeks, update to p=quarantine
3. Monitor for issues before considering p=reject

MX Record (Optional)

Only needed if you want to receive replies at your domain:

Type: MX
Name: @ (or your root domain)
Priority: 10
Value: [provided by Penna if applicable]

Step 3: Add Records to Your DNS Provider

Instructions vary by provider. Here are common ones:

Cloudflare

1. Log into Cloudflare
2. Select your domain
3. Go to DNS → Records
4. Click Add record
5. Select record type (TXT, MX, etc.)
6. Enter name and value
7. Click Save
8. Repeat for each record

GoDaddy

1. Log into GoDaddy
2. Go to My Products → DNS
3. Scroll to Records
4. Click Add
5. Select record type
6. Enter details
7. Click Save

Namecheap

1. Log into Namecheap
2. Select your domain
3. Go to Advanced DNS
4. Click Add New Record
5. Fill in details
6. Click Save All Changes

Google Domains

1. Log into Google Domains
2. Select your domain
3. Click DNS
4. Scroll to Custom resource records
5. Add each record
6. Click Add

AWS Route 53

1. Open Route 53 console
2. Select your hosted zone
3. Click Create record
4. Enter record details
5. Click Create records

Step 4: Verify Configuration

After adding DNS records:

1. Return to Penna dashboard
2. Go to Settings → Domain
3. Click "Verify Domain"
4. Penna will check your DNS records

Verification timing:

• Usually completes in 10-30 minutes
• Can take up to 48 hours for DNS propagation
• Check back if not immediate

Verification checks:

• ✅ SPF record found and correct
• ✅ DKIM record found and correct
• ✅ DMARC record found and correct
• ✅ Domain ownership verified

Step 5: Test Your Setup

Once verified, send a test email:

1. Go to Compose
2. Create a test newsletter
3. Send to your personal email
4. Check:
   • Email arrives
   • From address shows your@yourdomain.com
   • Not in spam
   • Headers show SPF/DKIM pass

Check Email Headers

To verify proper configuration:

Gmail:

1. Open the test email
2. Click three dots (⋮)
3. Select "Show original"
4. Look for:
   • SPF: PASS
   • DKIM: PASS
   • DMARC: PASS

Outlook:

1. Open email
2. Click File → Properties
3. Check Internet headers

Troubleshooting

Verification Fails

Common issues:

1. DNS not propagated yet

• Wait 24-48 hours
• Check propagation: https://dnschecker.org

2. Incorrect record value

• Copy-paste carefully from Penna dashboard
• No extra spaces or characters
• Check for truncation in long values

3. Duplicate SPF records

• Only one SPF record allowed
• Merge multiple into one

4. Wrong record name/host

• @ for root domain
• Full subdomain for DKIM (penna._domainkey.yourdomain.com)
• Check your DNS provider's syntax

Emails Still Going to Spam

Even with custom domain configured:

Check:

1. DNS records verified in Penna
2. Wait 24-48 hours for reputation to build
3. Review content for spam triggers
4. Warm up new domain gradually
5. Check sender reputation: https://senderscore.org

See: Avoiding Spam Folders

SPF Too Long Error

SPF records have a 255 character limit and 10 DNS lookup limit.

Solution:

• Use SPF flattening services
• Remove unused includes
• Consider subdomain delegation

Domain Warming

For new domains, warm up gradually:

Week 1: Send to 50-100 most engaged subscribers
Week 2: Double to 100-200
Week 3: Double to 200-400
Week 4+: Continue doubling until full list

Why: Sudden volume from new domain triggers spam filters.

Best Practices

Use Subdomain for Email

Option 1: Root domain (common)

From: newsletter@yourdomain.com

Option 2: Subdomain (advanced)

From: newsletter@mail.yourdomain.com

Why use subdomain:

• Isolates email reputation from website
• Protects main domain if issues occur
• Separate tracking and monitoring

When to use root:

• Simpler setup
• Better brand recognition
• Lower volume sending

Monitor Reputation

Tools to track:

• Google Postmaster Tools: Gmail-specific metrics
• Microsoft SNDS: Outlook metrics
• SenderScore: Overall reputation (aim for 80+)

Set up monitoring:

1. Google Postmaster: https://postmaster.google.com
2. Add your domain
3. Verify ownership
4. Monitor weekly

Keep Records Updated

Regular maintenance:

• Review DNS records quarterly
• Check for expiring DKIM keys
• Update DMARC reports address
• Monitor for unauthorized usage

Document Your Setup

Keep records of:

• DNS configuration
• Verification dates
• Provider access info
• Record update history
• Troubleshooting notes

Multiple Domains

Can you use multiple domains?

Yes, you can configure multiple:

• Different brands/products
• Regional variations
• Separate marketing vs transactional

Setup:

1. Add each domain separately in Penna
2. Configure DNS for each
3. Verify each domain
4. Select which domain per newsletter

Removing a Domain

To remove a custom domain:

1. Go to Settings → Domain
2. Select the domain
3. Click "Remove Domain"
4. Confirm removal

Note: Your newsletters will revert to Penna's shared sending domain. Clean up DNS records afterward.

Security Considerations

Protect Your DNS

Best practices:

• Enable 2FA on DNS provider
• Use strong passwords
• Limit access to DNS admin
• Monitor for unauthorized changes
• Keep DNS provider access secure

DMARC Reporting

Set up DMARC reports to monitor:

• Who's sending from your domain
• SPF/DKIM pass rates
• Potential spoofing attempts

DMARC report addresses:

rua=mailto:dmarc@yourdomain.com

Use a DMARC analyzer service or monitor manually.

Advanced Configuration

Separate Sending Subdomain

For high-volume or multiple use cases:

Marketing: marketing.yourdomain.com
Transactional: transact.yourdomain.com
Newsletter: news.yourdomain.com

Each has separate reputation and DNS records.

Custom Return-Path

Advanced setup for bounce handling:

Return-Path: bounce@yourdomain.com

Configured in Penna advanced settings.

BIMI (Brand Indicators)

Display your logo in Gmail (requires DMARC p=quarantine/reject):

Type: TXT
Name: default._bimi.yourdomain.com
Value: v=BIMI1; l=https://yourdomain.com/logo.svg

Requires VMC (Verified Mark Certificate) for Gmail.

Checklist

Setup: ✅ Domain added in Penna
✅ SPF record added to DNS
✅ DKIM record added to DNS
✅ DMARC record added to DNS
✅ DNS propagation complete
✅ Domain verified in Penna
✅ Test email sent and delivered
✅ SPF/DKIM/DMARC passing in headers

Monitoring: ✅ Google Postmaster Tools configured
✅ SenderScore checked (80+)
✅ DMARC reports received
✅ No blocklist listings
✅ Regular reputation monitoring scheduled

Resources

• Email Deliverability
• Avoiding Spam
• DNS Checker Tool
• MXToolbox

Tip: Take your time with DNS configuration - accuracy matters more than speed. Once properly set up, a custom domain is one of the best investments for email deliverability.