Summary
The decision of whether to use a shared pool of dedicated IPs or separate IPs with subdomains for multiple newsletters hinges on control, volume, and risk tolerance. Sharing a dedicated IP pool internally, with all senders adhering to best practices and sending legitimate opt-in mail, can be viable and efficient. However, this approach requires careful management and can be risky if sending practices vary. Using separate IPs and subdomains isolates reputation issues, ensuring that problems with one newsletter don't affect others. High-volume senders generally benefit from dedicated IPs, which offer greater control over sender reputation. Regardless of the IP strategy, proper email authentication (SPF, DKIM, DMARC) and consistent sending patterns with good engagement are essential for maintaining deliverability. Also, IP warmup is important when using dedicated IPs.
Key findings
- Shared Pool Viability: Shared IP pools can be effective when senders adhere to best practices, send legitimate opt-in mail, and maintain consistent sending volumes.
- Risk in Mixed Environments: Shared IP pools are riskier in mixed environments with varying sending practices; lack of control over other senders can negatively impact reputation.
- Isolation with Separate IPs/Subdomains: Using separate IPs and subdomains isolates reputation issues, preventing deliverability problems with one newsletter from affecting others.
- High Volume and Dedicated IPs: Dedicated IPs offer greater control over sender reputation and are generally recommended for high-volume senders.
- Authentication is Crucial: Proper email authentication (SPF, DKIM, DMARC) is essential for verifying sender identity and improving deliverability, regardless of the IP strategy.
- IP Warmup Importance: Warming up new IPs gradually is crucial for establishing a positive reputation with ISPs when using dedicated IPs.
- Domain Choice Matters: The choice of domain strategy (separate vs. consolidated domains) impacts the segmentation of sending reputation.
Key considerations
- Control Over Sending Practices: Assess the level of control you have over the sending practices of all senders sharing an IP pool.
- Sending Volume and Consistency: Consider your sending volume and consistency when choosing between shared and dedicated IPs.
- Importance of Reputation Isolation: Evaluate the importance of isolating reputation issues across different newsletters.
- Authentication Implementation: Ensure proper implementation of SPF, DKIM, and DMARC to authenticate your emails.
- Sender Reputation Monitoring: Monitor sender reputation metrics (e.g., spam complaints, engagement) to identify and address any deliverability issues.
- Best Practices Adherence: Adhere to email deliverability best practices to maintain a positive sender reputation.
- IP Warmup Strategy: Implement a proper IP warmup strategy when transitioning to dedicated IPs.
What email marketers say
9 marketer opinions
The question of whether to use a shared pool of dedicated IPs or separate IPs for multiple newsletters with different subdomains elicits varied recommendations, largely dependent on volume, control, and risk tolerance. Shared IP pools can be advantageous if you control all sending practices and volumes are consistent, allowing for efficient resource utilization. However, they pose a risk if sending practices are inconsistent or if you lack control over the other senders sharing the pool, as their actions can negatively impact your sender reputation. Separate IPs and subdomains offer better isolation of reputation issues; if one newsletter encounters deliverability problems, it won't necessarily affect the others. Regardless of the IP strategy, proper email authentication (SPF, DKIM, DMARC) and a consistent sending pattern with good engagement are crucial for maintaining a positive sender reputation and achieving optimal deliverability.
Key opinions
- Shared Pools (Controlled): Shared IP pools can be effective if you control all sending practices, volumes are consistent, and all mail is opt-in. This helps smooth volume across IPs.
- Shared Pools (Uncontrolled): Shared IPs pose a risk if you don't control the sending practices of all entities sharing the IP, potentially harming your sender reputation.
- Separate IPs/Subdomains: Separate IPs and subdomains isolate reputation issues, preventing problems with one newsletter from affecting others.
- Volume Threshold: Dedicated IPs are generally recommended for high-volume senders (e.g., >50,000 emails/month), while shared IPs may be suitable for lower volumes.
- Authentication: Proper email authentication (SPF, DKIM, DMARC) is crucial for verifying the sender's identity and improving deliverability, regardless of the IP strategy.
- Subdomains: The subdomain and domain reputations are the most important factor for ensuring deliverability. Use them to isolate brands.
Key considerations
- Control: Assess the level of control you have over sending practices. If you control all aspects of sending, a shared pool might be feasible.
- Volume: Consider the volume of emails you send. High-volume senders generally benefit more from dedicated IPs.
- Isolation: Determine the importance of isolating reputation issues. If isolation is critical, separate IPs and subdomains are preferable.
- Authentication: Ensure proper email authentication is in place to verify the sender's identity and improve deliverability.
- Sender Reputation: Monitor sender reputation metrics (spam complaints, engagement) and maintain consistent sending patterns to improve deliverability.
- Segmentation: Consider segmenting email traffic by type or brand to maintain better control over deliverability.
Marketer view
Email marketer from Mailjet shares that dedicated IP pools give you control over your sender reputation, which is crucial for maintaining high deliverability. This means that your sending reputation isn’t affected by the activities of other senders who are sharing an IP address.
24 Aug 2021 - Mailjet
Marketer view
Email marketer from Litmus shares that sender reputation is influenced by factors like email volume, spam complaints, and engagement rates. A consistent sending pattern and high engagement can improve your sender reputation, regardless of whether you use shared or dedicated IPs. They did not answer shared pool directly but gave key information about IP reputation.
28 Dec 2023 - Litmus
What the experts say
5 expert opinions
The experts offer a nuanced view on using shared pools of dedicated IPs versus separate IPs for multiple newsletters. If all data is legitimate opt-in and the sending volume is consistent, a shared pool managed internally can be viable. The number of IPs needed depends on volume, and platform recommendations should be considered. Maintaining distinct domains for each newsletter is recommended for isolating deliverability problems and preserving domain reputation. Dedicated IPs offer the best control over sender reputation, but require adherence to best practices and consistent sending. Warming up new IPs is crucial for establishing a positive reputation with ISPs.
Key opinions
- Shared Pool Viability: Shared IP pools can be viable if the data is legit opt-in and the sending volume is consistent across all newsletters, but only if all mail streams are controlled.
- IP Quantity: The required number of IPs depends on sending volume and platform recommendations. A starting point of 5-7 IPs may be suitable for a substantial volume, but always check vendor recommendations.
- Domain Isolation: Maintaining distinct domains for each newsletter is recommended to isolate deliverability problems and protect domain reputation.
- Dedicated IP Control: Dedicated IPs offer the greatest control over sender reputation, but they require adherence to best practices and consistent sending volumes.
- IP Warmup: Gradual IP warmup is essential for establishing a positive reputation with ISPs when transitioning to a dedicated IP.
Key considerations
- Data Quality: Ensure all data used for newsletters is legitimate opt-in to maintain a positive sender reputation.
- Volume Consistency: Assess whether sending volumes are consistent across all newsletters. Inconsistent volumes may make a shared pool less suitable.
- Platform Recommendations: Consult the recommendations of your email sending platform (e.g., Sendgrid) regarding the appropriate number of IPs for your sending volume.
- Best Practices: Adhere to email deliverability best practices, such as proper authentication (SPF, DKIM, DMARC) and avoiding spam triggers.
- Reputation Monitoring: Monitor sender reputation metrics to identify and address any deliverability problems promptly.
- Domain Choice: Carefully consider the impact of consolidating versus separating email domains per newsletter.
Expert view
Expert from Email Geeks suggests keeping different domains for each newsletter, since domain reputation is well handled by Gmail, and this will help you isolate Gmail problems that may come up in the future. The admin work to switch it all over + that would mean a bit of a reset of domain reputation for some of them, makes me think it wouldn't be worth it.
25 Jun 2021 - Email Geeks
Expert view
Expert from Word to the Wise Laura Atkins explains the importance of IP warmup, particularly when transitioning to a dedicated IP. She emphasizes the need to gradually increase sending volume to establish a positive reputation with ISPs. She does not directly discuss shared pools vs separate IPs but explains the need to maintain IP reputation which is key for email deliverability.
22 Apr 2023 - Word to the Wise
What the documentation says
4 technical articles
The documentation emphasizes several key aspects of email deliverability related to IP addresses and sender reputation. Dedicated IP addresses offer control over sender reputation, particularly beneficial for high-volume senders with consistent sending practices. IP pools enable segmentation of mail streams, allowing for isolation of reputation issues across different types of emails or brands, whether implemented through separate IPs or subdomains. Maintaining a good sender reputation is crucial, and authentication methods like SPF, DKIM, and DMARC are essential for verifying sender identity and preventing spam.
Key findings
- Dedicated IP Control: Dedicated IP addresses offer complete control over sender reputation.
- IP Pool Segmentation: IP pools allow segmentation of mail streams by type or brand to isolate reputation issues.
- Sender Reputation: Maintaining a good sender reputation is crucial for email deliverability.
- Authentication: Authentication methods like SPF, DKIM, and DMARC are essential for verifying sender identity and preventing spam.
Key considerations
- Sending Volume: Consider your sending volume and consistency when choosing between dedicated and shared IPs.
- Reputation Management: Evaluate the level of control you want over your sender reputation.
- Segmentation Needs: Determine if you need to segment your email traffic by type or brand for reputation isolation.
- Authentication Setup: Implement SPF, DKIM, and DMARC to authenticate your emails and improve deliverability.
Technical article
Documentation from Amazon Web Services explains that dedicated IP addresses are suitable for senders who want to manage their own reputation. They provide complete control over the sending reputation, which is crucial for high-volume senders who can maintain consistent sending practices. They don't directly address shared pools vs. separate IPs for multiple newsletters but provides core information to help come to a conclusion.
6 Nov 2023 - Amazon Web Services
Technical article
Documentation from RFC explains that SPF (Sender Policy Framework) is an email authentication method designed to prevent spammers from sending messages on behalf of your domain. It specifies which mail servers are authorized to send email from your domain, improving deliverability.
27 Jul 2022 - RFC
Can I use two subdomains on one dedicated IP address for different email types?
Can one dedicated IP be mapped to multiple sub-domains for email?
How many subdomains should I use per dedicated IP address for email sending?
Is a dedicated IP address needed for sending 150K-200K emails per month?
Is a dedicated IP beneficial for high-volume email sending even without deliverability issues?
What are the pros and cons of sending email from subdomains vs a single domain with multiple IPs, and how can I optimize my signup process and sender reputation for a growing business with small sending volumes?
