Summary
For senders using shared IP addresses, the email service provider typically handles the IP's warming and ongoing reputation management. Therefore, individual senders usually do not need to perform manual IP warming. However, it is critically important to warm up your sending domain, as domain reputation is increasingly the primary factor influencing deliverability, even more so than IP reputation in many cases. Both IP and domain reputations are intertwined and contribute to overall sender trustworthiness, but senders on shared IPs must focus heavily on building and maintaining a strong domain reputation through consistent, high-engagement sending practices.
Key findings
- Shared IP Warming by ESP: For shared IP addresses, the email service provider (ESP) is typically responsible for the initial warming and ongoing management of the IP's reputation. Individual senders on shared IPs generally do not need to manually warm the IP itself.
- Crucial Domain Warming: Despite shared IPs being pre-warmed, warming up your sending domain is critical. A new or 'cold' sending domain, or one with past deliverability issues, requires a warm-up period to build a positive reputation with ISPs, irrespective of the IP type.
- Domain Reputation Dominance: While both IP and domain reputations contribute significantly to email deliverability, domain reputation is increasingly viewed as the more critical and influential factor for long-term sender success and inbox placement. It directly reflects the sender's trustworthiness and brand identity.
- Interplay of Reputations: IP and domain reputations are interconnected and influence each other. ISPs often treat each domain/IP combination as a unique identifier, and reputation can flow both up and down between them. A strong domain reputation can provide resilience even if there's temporary bleed-over from a shared IP pool.
- Google Postmaster Tools Insights: Google Postmaster Tools provides insights into both domain reputation (often tied to the DKIM signing domain) and IP reputation, offering a breakdown for different IP sets if multiple sending platforms are used.
Key considerations
- Sender Focus on Domain Reputation: Even on shared IP addresses, senders must actively build and maintain a strong domain reputation. This involves consistent good sending practices, focusing on high-quality content, fostering recipient engagement, managing unsubscribes effectively, and minimizing spam complaints and bounce rates.
- Understanding GPT Limitations: While Google Postmaster Tools (GPT) offers valuable insights into both domain and IP reputation, it's important to recognize that a low reputation score in GPT doesn't always directly correlate with poor mail delivery. It's a useful indicator but not the sole determinant of inbox placement.
- Considering Dedicated IP for Volume: For senders with high monthly email volumes or specific frequency needs, especially during a platform migration, assessing whether a dedicated IP address is a better long-term solution than a shared IP is advisable. Dedicated IPs require specific warming strategies managed by the sender.
- Soft Warm-Up for New Domains: For new sending domains, even on pre-warmed shared IPs, a gradual 'soft warm-up' of sending volume is a good practice. This helps establish trust and a positive reputation with Internet Service Providers (ISPs) from the outset.
What email marketers say
10 marketer opinions
For email marketers, navigating deliverability on shared IP addresses means recognizing distinct responsibilities for IP and domain reputation. While the email service provider typically manages the pre-warming and ongoing reputation of shared IPs, the sender remains entirely accountable for their domain's reputation. This brand-specific standing, built through sending habits and recipient engagement, has become the dominant factor in determining inbox placement. Consequently, even with a pre-warmed IP, a new or 'cold' domain requires a meticulous warm-up process to establish trust with internet service providers.
Key opinions
- ESP Manages Shared IP Warming: On shared IP addresses, the email service provider (ESP) is typically responsible for pre-warming the IP and managing its collective reputation, eliminating the need for individual senders to perform manual IP warming.
- Domain Reputation Dominates: Domain reputation, which encompasses your brand's sending practices, content quality, and recipient engagement, has increasingly become the primary and most influential factor in determining email deliverability and inbox placement, often outweighing IP reputation.
- Domain Warming is Crucial: Despite using pre-warmed shared IPs, a new or 'cold' sending domain, or one with a history of deliverability issues, still requires a dedicated warm-up period to build a positive and trusted reputation with Internet Service Providers (ISPs).
- Interconnected Reputations: Both IP and domain reputations are interconnected and contribute to overall sender trustworthiness. While a poor shared IP reputation can temporarily affect a domain, a strong domain reputation provides significant resilience and helps maintain deliverability.
Key considerations
- Sender's Domain Responsibility: Email marketers on shared IPs must prioritize building and maintaining a robust domain reputation, as it is entirely their responsibility and directly reflects their brand's trustworthiness to ISPs. This requires consistent adherence to best practices.
- Strategic Domain Warming: For new or cold domains, even when using pre-warmed shared IPs, a careful 'soft warm-up' is essential. This involves starting with small volumes sent to highly engaged subscribers and gradually increasing audience size and sending frequency to establish trust.
- Cultivating Engagement: To strengthen domain reputation, focus on sending high-quality, relevant content that encourages recipient engagement. Actively manage unsubscribes, minimize spam complaints, and ensure low bounce rates through diligent list hygiene.
- Leveraging Analytics: Utilize tools like Google Postmaster Tools to monitor your domain's and IP's reputation, understanding that while IP reputation on shared pools is managed, your domain's performance directly impacts your brand's deliverability.
Marketer view
Email marketer from Email Geeks explains that Google Postmaster Tools allows users to see the reputation of the domain used for DKIM signing, and a breakdown of the reputation for each set of IP addresses used if sending from multiple platforms.
4 Mar 2022 - Email Geeks
Marketer view
Marketer from Validity's blog explains that while IP reputation is about the sending server's history, domain reputation is tied to the brand and its sending practices, including content and engagement. On shared IPs, the IP reputation is managed by the ESP, but your domain reputation is entirely yours and requires warming if new or if you've had deliverability issues. They are interconnected, as a poor IP reputation on a shared pool can temporarily impact your domain, but a strong domain reputation provides resilience.
3 Aug 2024 - Validity Blog
What the experts say
6 expert opinions
Expanding on the dynamics of email deliverability, it's evident that while your email service provider typically manages the pre-warming and ongoing reputation of shared IP addresses, your domain's reputation has become an even more pivotal factor. Both IP and domain reputations are essential, reflecting distinct aspects of your sending history that internet service providers evaluate. Domain reputation is increasingly prioritized because it's more resilient to sender changes and more difficult for malicious actors to discard, establishing a persistent identifier of your sending practices across different infrastructures.
Key opinions
- Shared IP Warming by ESP: Email warming is primarily a technique used for dedicated IP addresses; for senders on shared IP addresses, the email service provider (ESP) is typically responsible for the IP warming process and ongoing reputation management.
- Domain Reputation's Growing Significance: In modern email deliverability, domain reputation has become increasingly significant, often playing a larger role than IP reputation, as it's harder for malicious senders to discard and is portable across different sending infrastructures.
- Interplay of Reputations: Both IP address reputation and domain reputation are crucial, intertwined components of overall sender reputation, with Google treating each domain-IP combination as its own identifier and reputation flowing both up and down between them.
- Authentication and Domain Trust: Domain reputation reflects the history of mail from that domain and is often tied directly to authentication checks such as SPF, DKIM, and DMARC, making these protocols vital for establishing sender trust.
- GPT's Role in Monitoring: Google Postmaster Tools provides insights into both domain reputation and IP reputation, although it's important to note that a low reputation score in GPT does not always directly indicate that mail will fail to reach the inbox.
Key considerations
- Strategic Use of Dedicated IPs: For senders with high monthly email volumes or specific sending frequency requirements, especially during a platform migration, assessing whether a dedicated IP address is a better long-term solution than a shared IP is advisable, as dedicated IPs require specific warming strategies managed directly by the sender.
- Navigating Reputation Shifts: Moving email to a new IP address, even if it's a new shared IP, can initially make Internet Service Providers (ISPs) suspicious due to the nature of how they track domain/IP combinations, emphasizing the importance of consistent sending practices.
- Aligning IP and Domain Health: To achieve optimal deliverability, both your IP address reputation and your domain reputation should ideally be aligned and consistently positive, as ISPs consider both in their evaluation of incoming mail.
Expert view
Expert from Email Geeks explains that both domains and IPs need to be warmed up, not just one or the other. Depending on monthly total volume and mail frequency, a dedicated IP might be worth considering during migration.
19 Jun 2023 - Email Geeks
Expert view
Expert from Email Geeks explains that on shared IPs, there can be bleed-over reputation. Google treats each domain/IP combination as its own identifier, so moving mail to a new IP can make them suspicious. Reputation flows up and down. Google Postmaster Tools (GPT) provides domain reputation and IP reputation, but it doesn't always indicate mail delivery, as sometimes low reputation can still lead to 100% inbox delivery.
24 Sep 2023 - Email Geeks
What the documentation says
3 technical articles
The consensus among leading email service providers is that individual senders on shared IP addresses do not need to perform manual IP warming, as this is managed by the provider. Instead, the primary focus for deliverability shifts heavily towards cultivating a strong domain reputation. While both IP and domain reputations contribute to overall sender trustworthiness, domain reputation is increasingly seen as the more critical factor for long-term success and inbox placement, directly reflecting a sender's consistent practices and recipient engagement.
Key findings
- Shared IP Warming - Provider Responsibility: Email service providers are responsible for pre-warming and maintaining the collective reputation of shared IP addresses, eliminating the need for individual senders to perform manual IP warming.
- Domain Reputation's Primacy: Domain reputation is now widely considered the more critical and influential factor for email deliverability and long-term sender success, especially for those using shared IP addresses.
- Domain Warming is Essential: Even when using pre-warmed shared IPs, a diligent domain warming process is crucial for new or 'cold' domains to establish trust, involving gradual volume increases and consistent high engagement.
- Interplay of Reputations: Both IP and domain reputations are vital and interact to determine overall deliverability, with domain reputation increasingly serving as the true reflection of a sender's trustworthiness and sending practices.
Key considerations
- Prioritize Domain Health: Senders utilizing shared IP addresses must diligently focus on building and maintaining a robust domain reputation through high-quality content, fostering recipient engagement, and effectively managing feedback loops.
- Consistent Engagement for Trust: Achieving optimal deliverability heavily depends on consistently sending relevant content that drives positive recipient engagement, which directly contributes to a strong and trusted domain reputation.
- No Manual IP Warming for Shared: Understand that manual IP warming is not required when using shared IP addresses, as the email service provider is responsible for managing this aspect of the IP's reputation.
Technical article
Documentation from SendGrid explains that dedicated IP addresses require warming to build a good sending reputation, but shared IPs are pre-warmed by the provider. On shared IPs, the focus shifts more towards building a strong domain reputation through consistent, high-engagement sending, as IP reputation is collectively managed. Both IP and domain reputation contribute to deliverability, with domain reputation becoming increasingly important.
30 Jun 2024 - SendGrid Documentation
Technical article
Documentation from Mailgun states that shared IPs are generally pre-warmed, meaning users don't need to manually warm the IP itself. However, even on shared IPs, it is crucial to warm up your domain by gradually increasing sending volume and maintaining good engagement to build a positive domain reputation. Both IP and domain reputation influence deliverability, but domain reputation is often seen as the more critical factor for long-term sender success.
23 Dec 2022 - Mailgun Documentation
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