Is it better to use a shared pool of dedicated IPs or separate IPs for multiple newsletters with different subdomains?
Michael Ko
Co-founder & CEO, Suped
Published 12 Jun 2025
Updated 17 Aug 2025
7 min read
When you are managing multiple newsletters, each potentially with its own subdomain and sending from different Mail Transfer Agents (MTAs) through your Email Service Provider (ESP), a critical question arises: should you assign each newsletter its own dedicated IP address or consolidate them into a shared pool of dedicated IPs? This decision significantly impacts your email deliverability, sender reputation, and overall operational efficiency.
The choice between these two IP allocation strategies depends on several factors, including your total sending volume, the consistency of your sends, the quality of your subscriber lists, and your approach to risk management. Understanding the nuances of each option is key to optimizing your inbox placement and maintaining a healthy sender reputation across all your newsletter streams.
Understanding IP allocation strategies
A dedicated IP address is one that is exclusively assigned to your sending domain. This means your sending reputation is solely your responsibility, unaffected by other senders. Conversely, a shared IP pool involves multiple senders using the same IP addresses, where the reputation is a collective effort. The question in a multi-newsletter scenario isn't just about dedicated versus shared, but whether to create your own shared pool from your own dedicated IPs.
If all your newsletters are legitimate, permission-based, and maintain high engagement, using a self-managed shared pool (where all IPs are dedicated to your organization) can be highly advantageous. This approach allows you to distribute your total sending volume across a set number of IPs, potentially smoothing out delivery patterns and ensuring consistent volume for each IP, even if individual newsletters have varying send frequencies or sizes. For more insights on general IP choices, you can read about dedicated vs. shared IPs.
This strategy contrasts with assigning a single dedicated IP to each newsletter. While that provides ultimate isolation for each brand, it could also mean each IP struggles to build sufficient volume and consistency, especially for smaller newsletters. A personal shared pool can help overcome this, as the collective volume ensures all IPs are adequately warmed and actively used, which is crucial for maintaining a good sender reputation.
Dedicated IP per newsletter
Reputation isolation: Each newsletter's email reputation is distinct, preventing one's poor performance from affecting others.
Fine-grained control: Allows for specific IP warming and management strategies for each newsletter.
Potential for low volume: Smaller newsletters may not send enough volume to maintain a strong IP reputation.
Higher cost: Acquiring and managing a dedicated IP for each newsletter can be significantly more expensive.
Cost-effective: Requires fewer dedicated IPs for the total volume.
Reputation sharing: If one newsletter performs poorly, it can impact the reputation of the entire pool.
Centralized management: Simplifies IP management through a single MTA account.
The role of subdomains in multi-newsletter setups
Regardless of your IP strategy, maintaining separate subdomains for each newsletter is generally recommended. This is a critical aspect of managing Google and Yahoo requirements, especially with recent changes that emphasize domain reputation over IP reputation. By segmenting your sending via subdomains, you can isolate any deliverability issues to a specific newsletter without impacting the reputation of your other brands or your primary domain. You can learn more about segmenting email streams with subdomains.
For example, if one newsletter experiences a surge in spam complaints, the negative impact will primarily be contained to its specific subdomain's reputation, rather than affecting the entire IP pool or your root domain. This allows for easier identification and resolution of problems, as well as preserving the deliverability of your other newsletters. This practice aligns with general best practices for complex email sending operations, as explored in guides on dedicated vs. shared IPs.
While subdomains help with domain reputation, using a single sending domain for all newsletters, even with multiple IPs, introduces significant risk. If one newsletter's content or list quality causes a major issue, it could jeopardize the deliverability of all your email streams that share that single domain. This can lead to widespread inbox placement issues or even being put on a blacklist (or blocklist), making recovery challenging. The administrative effort to switch all newsletters to a new shared domain would also be substantial, including resetting domain reputation.
Best practices for subdomain usage
Isolate streams: Use a different subdomain for each newsletter or distinct email stream (e.g., newsletter1.yourdomain.com, newsletter2.yourdomain.com).
Reputation management: This helps maintain separate sender reputations for each email program, crucial for subdomain reputation management.
Compliance and monitoring: Easier to track performance, identify issues, and apply DMARC policies specific to each newsletter.
Volume, consistency, and risk management
High-volume sending, such as 5 million emails per week per newsletter (totaling 9-11 million a day across all newsletters), necessitates careful IP management. While individual newsletters might have fluctuations, a personal shared pool of dedicated IPs can help maintain a more consistent overall sending volume, which is vital for building and sustaining a good IP reputation. Internet Service Providers (ISPs) favor consistent senders.
If your send patterns are steady, even with high daily volumes spread across several hours, a pool of 7 dedicated IPs for 9-11 million daily sends can be an appropriate starting point. Some general guidelines suggest one IP for every 100,000 emails per hour or 2 million emails per day, though these are estimations and can vary based on your ESP's infrastructure and the specific ISPs you are sending to. For very large email lists, you might consider multiple dedicated IPs.
This setup also offers a layer of risk mitigation. While a personal shared pool implies some shared IP reputation risk among your own brands, it's generally much lower than using a public shared pool where you don't control other senders' practices. If a minor issue arises with one newsletter, the collective volume and good standing of the other newsletters in your pool can help absorb the impact, preventing a total deliverability collapse. The key is that all your newsletters are legitimate and well-managed.
Volume threshold
IP requirement (estimated)
Up to 50,000 emails/week
Shared IP (ESP's pool)
50,000 to 250,000 emails/day
1-2 dedicated IPs
250,000 to 1 million emails/day
2-4 dedicated IPs
Over 1 million emails/day
4+ dedicated IPs (in a pool)
Making the right decision for your newsletters
For a scenario involving 15 newsletters, each with its own subdomain and significant sending volume (e.g., millions per week), using your own shared pool of dedicated IPs is likely the most effective and cost-efficient strategy. This allows for centralized management of your MTA relationship with your ESP, providing greater control while leveraging the benefits of a collective sending volume to maintain strong IP reputation.
The number of IPs in your personal shared pool should be adequate for your total aggregate volume, with some buffer for growth. If you currently have 7 dedicated IPs for a total daily volume of 9-11 million emails distributed across multiple newsletters, this allocation sounds reasonable to start. It gives you room to grow while maintaining the consistency needed for deliverability. You can learn more about when to use a shared IP versus a dedicated IP.
Ultimately, the best approach combines smart IP allocation with robust subdomain strategy. This enables you to maximize deliverability, minimize costs, and isolate potential issues, ensuring each of your newsletters reaches its intended audience effectively. Continuous monitoring of your sender reputation, blocklist (or blacklist) status, and engagement metrics for each subdomain and IP in your pool is essential for long-term success.
Conclusion
For operations with distinct email streams like multiple newsletters, using a pool of dedicated IPs under your own management generally offers the best balance of control, cost-effectiveness, and deliverability performance. This allows for the spreading of volume to ensure consistent sending patterns, which ISPs value highly.
Coupling this with separate subdomains for each newsletter provides crucial insulation for your domain reputation, ensuring that any deliverability issues remain isolated. This combined strategy empowers you to manage a complex email ecosystem efficiently and maintain high inbox placement rates across all your brand communications.
Views from the trenches
Best practices
Maintain separate subdomains for each newsletter to isolate domain reputation.
Utilize a personal shared pool of dedicated IPs to smooth out overall sending volume.
Ensure all newsletters maintain high engagement and low complaint rates to protect the shared IP pool reputation.
Monitor IP and domain reputation regularly using postmaster tools and blocklist checkers.
Common pitfalls
Using a single domain for all newsletters can lead to widespread deliverability issues if one stream performs poorly.
Assigning too many dedicated IPs for insufficient volume per IP can hinder reputation building.
Ignoring inconsistent sending volumes, which can negatively impact IP warming and reputation.
Not properly warming up new dedicated IPs before increasing volume across the pool.
Expert tips
For large volumes, consider an IP allocation of roughly 1 IP for every 100,000 emails per hour or 2 million per day, adjusting based on actual send patterns.
A personal shared IP pool is ideal when all sending is internal and legitimate, as it offers better volume consistency than individual IPs for smaller streams.
Prioritize separating email streams by subdomains to mitigate risks, as domain reputation is increasingly important to ISPs.
Regularly review your email sending infrastructure to ensure it scales with your business needs and adapts to evolving sender requirements.
Expert view
Expert from Email Geeks says that if all the mail is legitimate and opt-in, considering a self-managed shared pool and spreading the volume around is a good strategy, citing successful implementations for multi-brand companies.
2024-11-06 - Email Geeks
Expert view
Expert from Email Geeks says that shared pools are riskier in mixed environments, but when you are the sole sender in the pool, combining them helps with consistent sending volumes, especially if not every newsletter sends daily.
