The Right Way to Warm Up a New IP Address for Email Sending

Why IP Warm-up is Essential

A new IP address has no sending history or reputation. Internet Service Providers (ISPs) treat emails from unknown IPs with caution, often filtering them to spam or blocking them entirely. The warm-up process gradually introduces your IP to ISPs while demonstrating responsible sending practices.

Key Principle: Warm-up is about building trust through consistent, high-engagement sending patterns that signal to ISPs you're a legitimate sender.

This guide outlines the mechanical process of warming up an IP address, focusing on volume progression, engagement monitoring, and strategic sending patterns that build positive reputation.

Pre-Warm-up Preparation

Configure Email Authentication

Ensure SPF, DKIM, and DMARC records are properly configured before sending any emails. Authentication failures during warm-up can permanently damage your reputation.

Verification: Send test emails to verify authentication passes before beginning the warm-up process.

Segment Your Email List

Identify your most engaged subscribers—those who regularly open, click, and interact with your emails. This segment will receive your initial warm-up emails.

Criteria: Subscribers who have engaged within the last 30-60 days, with open rates above 40%.

Prepare High-Value Content

Create content specifically designed to generate high engagement during the warm-up period. This should be your most valuable, relevant content.

Content Strategy: Educational content, exclusive offers, or re-engagement campaigns work well for warm-up.

The 4-Week Warm-up Schedule

This schedule assumes a target volume of 100,000 emails per month. Adjust volumes proportionally for your specific sending needs.

Week 1: Foundation Building (Days 1-7)

Daily Volume Progression

Day 1: 50-100 emails to most engaged segment
Day 2: 100-200 emails
Day 3: 200-400 emails
Day 4: 400-800 emails
Day 5: 800-1,600 emails
Day 6: 1,600-3,000 emails
Day 7: 3,000-5,000 emails

Key Activities

Send only to highly engaged subscribers
Monitor open and click rates closely
Watch for any bounce or complaint issues
Maintain consistent sending times
Ensure authentication remains valid

Week 2: Gradual Expansion (Days 8-14)

Daily Volume Progression

Day 8: 5,000-7,000 emails
Day 9: 7,000-9,000 emails
Day 10: 9,000-12,000 emails
Day 11: 12,000-15,000 emails
Day 12: 15,000-18,000 emails
Day 13: 18,000-22,000 emails
Day 14: 22,000-25,000 emails

Key Activities

Expand to moderately engaged subscribers
Continue monitoring engagement metrics
Introduce different content types gradually
Maintain excellent list hygiene
Watch for any deliverability changes

Week 3: Volume Ramp-up (Days 15-21)

Daily Volume Progression

Day 15: 25,000-30,000 emails
Day 16: 30,000-35,000 emails
Day 17: 35,000-40,000 emails
Day 18: 40,000-45,000 emails
Day 19: 45,000-50,000 emails
Day 20: 50,000-55,000 emails
Day 21: 55,000-60,000 emails

Key Activities

Include less engaged but still active subscribers
Test different sending patterns and times
Monitor ISP-specific deliverability
Continue maintaining high engagement rates
Prepare for full-volume sending

Week 4: Stabilization (Days 22-28)

Daily Volume Progression

Day 22: 60,000-70,000 emails
Day 23: 70,000-80,000 emails
Day 24: 80,000-90,000 emails
Day 25: 90,000-100,000 emails
Day 26-28: Maintain target volume

Key Activities

Reach your target sending volume
Include your full active subscriber list
Establish consistent sending patterns
Monitor reputation across major ISPs
Implement ongoing monitoring procedures

Critical Monitoring Metrics During Warm-up

Engagement Metrics

Open Rates

Target: >25% during warm-up period

Action: If below 20%, slow volume increase

Click-Through Rates

Target: >3% during warm-up period

Action: If below 2%, improve content relevance

Reputation Metrics

Bounce Rates

Target: <2% overall bounce rate

Action: If above 5%, pause and clean list

Spam Complaint Rates

Target: <0.1% complaint rate

Action: If above 0.3%, immediately reduce volume

Adjustment Protocol

If any metric falls below target thresholds, immediately reduce sending volume by 50% and focus on improving that metric before continuing the warm-up progression. Never increase volume when engagement metrics are declining.

Optimal Sending Patterns and Timing

Temporal Distribution

Spread your daily volume across optimal sending times to maximize engagement and mimic natural email patterns.

Early Morning (6-9 AM) 15% of daily volume

Late Morning (9 AM-12 PM) 25% of daily volume

Early Afternoon (12-3 PM) 30% of daily volume

Late Afternoon (3-6 PM) 20% of daily volume

Evening (6-9 PM) 10% of daily volume

Content Rotation Strategy

Vary your content types during warm-up to demonstrate sending diversity and maintain engagement.

Educational Content Days 1-7

Newsletter Format Days 8-14

Promotional Content Days 15-21

Mixed Content Types Days 22-28

Note: Gradually introduce promotional content only after establishing strong engagement with non-promotional emails.

Troubleshooting Common Warm-up Issues

Issue: Low Engagement Rates

Symptoms: Open rates below 20%, click-through rates below 2%

Solution: Immediately reduce sending volume by 50%
Re-segment to focus on most engaged subscribers only
Improve subject lines and content relevance
Test different sending times
Do not increase volume until engagement improves

Issue: High Bounce Rates

Symptoms: Bounce rates above 5%, particularly hard bounces

Solution: Pause warm-up immediately
Thoroughly clean your email list
Remove all invalid and inactive addresses
Verify list quality before resuming
Restart from a lower volume point

Issue: Spam Complaints

Symptoms: Complaint rates above 0.3%, deliverability issues

Solution: Stop all sending immediately
Identify and remove complaining addresses
Review content for spam triggers
Ensure unsubscribe process is working
Consider extending warm-up timeline

Issue: Authentication Failures

Symptoms: Emails failing SPF, DKIM, or DMARC checks

Solution: Pause warm-up until fixed
Verify all authentication records are correct
Test authentication with multiple tools
Ensure DNS changes have fully propagated
Resume only after authentication passes consistently

Post-Warm-up Maintenance

After successfully completing the warm-up period, maintain your IP reputation through consistent, responsible sending practices.

Ongoing Best Practices

Maintain consistent sending volumes and patterns
Continue monitoring engagement metrics daily
Regularly clean your email list (monthly recommended)
Implement gradual volume changes, not sudden spikes
Maintain excellent authentication configuration
Monitor blacklist status weekly

Volume Change Protocol

For increases: Add no more than 20-30% volume weekly
For decreases: Gradual reduction preferred over sudden stops
Seasonal changes: Plan ahead and ramp up/down gradually
New list segments: Warm up gradually as with new IPs
Monitor metrics closely during any volume changes

Key Insight: A successfully warmed-up IP address is a valuable asset. Protect your investment through consistent, responsible sending practices that maintain the reputation you've built during the warm-up period.

Conclusion: The Mechanics of Successful IP Warm-up

IP warm-up is a systematic process that builds sender reputation through demonstrated responsible sending behavior. The key mechanical components are gradual volume progression, strategic audience segmentation, consistent high engagement, and careful metric monitoring.

By following this structured approach—starting with small volumes to highly engaged subscribers and gradually expanding while maintaining excellent engagement metrics—you establish positive sending patterns that ISPs recognize and reward with improved deliverability.

Final Recommendation: Treat IP warm-up as a necessary investment in your email infrastructure. Rushing the process or skipping steps will likely result in long-term deliverability issues that take much longer to fix than following the proper warm-up procedure.

What is an SPF Record?

An SPF (Sender Policy Framework) record is a type of DNS (Domain Name System) record that identifies which mail servers are permitted to send email on behalf of your domain. It's a critical email authentication method that helps protect your domain against spoofing and prevents your emails from being marked as spam.

Analogy: Think of an SPF record as a guest list for an exclusive event. Only the people (mail servers) on the list are allowed to enter (send emails from your domain).

When an email is received, the receiving mail server checks the SPF record of the sending domain to verify that the email came from an authorized server. If the sending server isn't listed in the SPF record, the email may be rejected or marked as spam.

Why is an SPF Record Needed?

Prevent Email Spoofing

Without SPF, attackers can easily forge the "From" address in emails to make them appear to come from your domain, leading to phishing attacks and damage to your reputation.

Improve Email Deliverability

Email providers like Gmail, Outlook, and Yahoo use SPF to verify sender authenticity. Proper SPF configuration increases the likelihood that your emails reach the inbox.

Build Sender Reputation

Consistently passing SPF checks helps build a positive sender reputation, which is crucial for successful email marketing campaigns and business communications.

Meet Industry Standards

SPF is part of the DMARC standard, which many organizations now require for accepting emails.

How SPF Improves Email Deliverability

Email service providers use complex algorithms to determine whether an email should be delivered to the inbox, spam folder, or rejected entirely. SPF plays a crucial role in this decision-making process.

When your domain has a properly configured SPF record, receiving mail servers can verify that your emails are legitimate. This verification builds trust and improves your sender score, which directly impacts deliverability rates.

Email sent from your domain

↓

Receiving server checks your SPF record

↓

Email authenticated → Higher deliverability

Note: SPF is just one component of email authentication. For maximum deliverability, it should be used in conjunction with DKIM and DMARC.

Understanding SPF Record Syntax

An SPF record is a TXT record in your DNS with a specific syntax. Here's a breakdown of the components:

v=spf1 include:_spf.google.com include:servers.mcsv.net ~all

Component	Description	Example
v=spf1	SPF version identifier	Mandatory prefix for all SPF records
include	Authorizes another domain's SPF record	include:_spf.google.com
ip4	Authorizes an IPv4 address or range	ip4:192.168.0.1
ip6	Authorizes an IPv6 address or range	ip6:2001:db8::/32
a	Authorizes the domain's A record IPs	a
mx	Authorizes the domain's MX record IPs	mx
~all	Soft fail for unauthorized servers	Emails from other servers are marked as suspicious
-all	Hard fail for unauthorized servers	Emails from other servers are rejected

How to Set Up SPF Records in Major DNS Providers

Cloudflare

Log in to your Cloudflare account and select your domain.
Navigate to the "DNS" section in the dashboard.
Click "Add record" and select "TXT" as the record type.
For the name, enter your domain (usually "@" for the root domain).
In the content field, enter your SPF record (e.g., v=spf1 include:_spf.google.com ~all).
Set the TTL (Time to Live) to "Auto" or your preferred value.
Click "Save" to create the record.

Note: Cloudflare may take a few minutes to propagate the DNS changes globally.

Namecheap

Log in to your Namecheap account and go to the "Domain List".
Click "Manage" next to the domain you want to configure.
Select "Advanced DNS" from the navigation menu.
Find the "HOST RECORDS" section and click "Add New Record".
Select "TXT Record" from the type dropdown.
For the host, enter "@" for the root domain or your subdomain.
In the value field, enter your SPF record.
Set the TTL to the recommended value (usually 1800 seconds).
Click the save icon (checkmark) to create the record.

GoDaddy

Sign in to your GoDaddy Domain Portfolio.
Click on your domain to access the Domain Settings page.
Under "Additional Settings", select "Manage DNS".
In the "Records" section, click "Add" to create a new record.
Select "TXT" as the record type.
For the host, enter "@" for the root domain.
In the "TXT Value" field, enter your SPF record.
Set the TTL to the desired value (1 hour is typical).
Click "Save" to add the record.

AWS Route 53

Log in to the AWS Management Console and open the Route 53 console.
In the navigation pane, choose "Hosted zones".
Select the hosted zone for your domain.
Choose "Create record".
Leave the record name blank for the root domain or enter a subdomain.
Select "TXT - Text" as the record type.
In the value field, enter your SPF record enclosed in quotes.
Set the TTL value as needed.
Click "Create records" to save.

Google Domains

Sign in to Google Domains with your account.
Select the domain you want to manage.
Click on "DNS" in the left navigation menu.
Scroll down to the "Custom resource records" section.
In the first field (@ for root domain or subdomain name), leave blank for root or enter subdomain.
Set the type to "TXT".
In the "TTL" field, enter the time in seconds (3600 is typical).
In the "Data" field, enter your SPF record.
Click "Add" to save the record.

SPF Record Best Practices

Do's

Use the ~all mechanism initially for soft fails
Regularly review and update your SPF record
Use the include mechanism for third-party email services
Keep your SPF record under 10 DNS lookups (limit is 10)
Test your SPF record using online validation tools

Don'ts

Don't create multiple SPF records for the same domain
Avoid using +all (pass all) as it defeats the purpose
Don't forget to include all email sending services you use
Avoid exceeding the 10 DNS lookup limit
Don't set TTL values too high when testing or making changes

Important: DNS changes can take up to 48 hours to propagate globally, though it's usually much faster. Always verify your SPF record after making changes.

Testing Your SPF Record

After setting up your SPF record, it's crucial to verify that it's working correctly. Here are some methods to test your SPF configuration:

Command Line

Use dig or nslookup commands to check your TXT records

Online Tools

Use websites like MXToolbox, SPF Record Testing Tools

Send Test Emails

Send emails to accounts on different providers and check headers

nslookup -type=TXT yourdomain.com

Conclusion

Implementing a proper SPF record is a fundamental step in securing your domain's email communications and improving deliverability. While the initial setup might seem technical, most DNS providers have simplified the process with user-friendly interfaces.

Remember that SPF is just one part of a comprehensive email authentication strategy. For maximum protection and deliverability, consider implementing DKIM and DMARC as well.

Final Tip: Regularly audit your SPF record, especially when adding new email marketing services or changing your email infrastructure. This ensures your record remains accurate and effective.