Summary
When utilizing a third-party Email Service Provider (ESP), ensuring strong email deliverability hinges on a combination of robust authentication protocols and a strategic approach to IP addresses. SPF, DKIM, and DMARC are foundational authentication methods that verify sender identity, authorize your ESP to send emails on your behalf, and build crucial trust with recipient mail servers. These protocols are indispensable for preventing emails from being flagged as spam and ensuring optimal inbox placement. While SPF is generally straightforward, careful attention to DKIM alignment and DMARC policy implementation is crucial, as an ESP's signing practices can affect DMARC's effectiveness beyond basic monitoring. Separately, the choice of IP address, whether shared or dedicated, significantly impacts deliverability. A dedicated IP provides complete control over your sending reputation, offering predictability and isolation for high-volume, consistent senders. However, for lower volumes or specific recipients like Gmail, a dedicated IP might not always provide an advantage and requires careful warm-up. Ultimately, beyond technical configurations, strong deliverability also relies on engaging content and a precise understanding of where emails are experiencing issues across various ISPs.
Key findings
- Authentication is Essential: SPF, DKIM, and DMARC are non-negotiable, fundamental protocols for email deliverability when using a third-party ESP. They verify sender identity, authorize the ESP to send emails on your domain's behalf, prevent spoofing, and significantly build trust with ISPs, thereby ensuring emails reach the inbox rather than being flagged as spam or phishing attempts.
- Dedicated IP Offers Control: A dedicated IP address, when used with a third-party ESP, allows senders to build and exclusively control their own sending reputation. This direct control can lead to more consistent and predictable inbox placement, particularly for high-volume, consistent senders who want to avoid their reputation being influenced by other users on shared IPs.
- DMARC Benefits and Caveats: DMARC provides a policy layer for how receiving servers should handle unauthenticated emails and offers reporting, collectively enhancing trust. However, its direct impact on delivery can be marginal. Marketers are advised against implementing a DMARC policy stronger than 'p=none' if domain-aligned DKIM is not fully supported or properly configured by the ESP, to avoid unintended deliverability issues.
- Shared IPs Leverage Collective Reputation: For senders with lower email volumes, shared IP addresses can be beneficial by leveraging the collective sending reputation of the ESP. While this pool can carry the risk of being affected by other users' practices, many ESPs diligently manage shared IP reputation, making it a viable option for many.
- Deliverability Beyond IPs and Authentication: Beyond authentication protocols and IP addresses, email content, links, and overall sender reputation health play a significant role in deliverability. Identifying specific ISPs where emails are not landing in the inbox is a critical first step in diagnosing and addressing deliverability challenges effectively.
Key considerations
- Ensure Proper Authentication Setup: Collaborate with your ESP to accurately configure SPF, DKIM, and DMARC DNS records for your domain. This foundational step is essential for establishing sender trust and avoiding spam folders, as it verifies your domain's legitimacy to recipient servers and authorizes the ESP to send on your behalf. While SPF is generally straightforward to implement, ensuring DKIM alignment with your domain is crucial, especially before moving beyond a DMARC p=none policy, as some ESPs may sign on their own domains rather than yours, which can impact DMARC effectiveness for strict policies.
- Assess IP Needs Based on Volume: Carefully consider whether a dedicated IP address is necessary for your email program. It offers complete control over your sending reputation and is particularly advantageous for high-volume, consistent senders who need predictable inbox placement and wish to isolate their deliverability performance from other ESP users. For lower sending volumes, shared IPs can be perfectly adequate, leveraging the collective reputation of the ESP, though they carry a minor risk of being affected by other users' sending habits. Dedicated IPs also require a careful warm-up period, and for certain ISPs like Gmail, they may not always provide an immediate advantage, sometimes even hindering deliverability during the warm-up phase if not managed correctly.
- Prioritize Content and Engagement: Even with strong authentication, message content and recipient engagement are critical deliverability factors. If SPF is correctly set up, issues often stem from content, links, or a lack of positive recipient interaction. Focus on crafting relevant, valuable emails that encourage opens and clicks to build a strong sender reputation, regardless of your IP strategy.
- Identify Specific Deliverability Issues: When troubleshooting deliverability problems, it is crucial to accurately pinpoint where emails are landing in spam. For instance, determining if the issue is with Gmail, private domains, or business domains will guide your troubleshooting approach, as the solutions can differ significantly based on the recipient's email environment.
What email marketers say
10 marketer opinions
Beyond the foundational elements, a sophisticated approach to email deliverability, especially when partnering with a third-party Email Service Provider (ESP), demands careful attention to both authentication protocols and IP strategy. SPF, DKIM, and DMARC serve as the critical pillars for establishing sender authenticity, enabling your ESP to legitimately dispatch emails on your behalf, and cultivating essential trust with recipient mail servers. These technical safeguards are paramount for ensuring emails bypass spam filters and consistently reach intended inboxes. While SPF is often straightforward, the nuances of DKIM alignment and thoughtful DMARC policy implementation, particularly regarding ESP signing practices, significantly influence their effectiveness. Concurrently, the choice between a shared or dedicated IP address profoundly shapes your sending reputation. A dedicated IP grants direct control and isolation of your reputation, proving highly beneficial for senders with substantial and consistent volumes. However, for lower volumes or specific recipient environments, a dedicated IP's benefits might be less pronounced, necessitating a strategic warm-up. Ultimately, comprehensive deliverability success extends beyond technical configurations, equally relying on compelling content, positive recipient engagement, and a diligent process of diagnosing and resolving specific deliverability roadblocks at various Internet Service Providers (ISPs).
Key opinions
- Auth as Trust Foundation: SPF, DKIM, and DMARC are pivotal for establishing a trustworthy sender reputation, allowing the ESP's infrastructure to send mail on your domain's behalf without being flagged as fraudulent, significantly boosting inbox placement.
- Dedicated IP for Reputation Autonomy: A dedicated IP address provides complete control over a sender's unique reputation, offering predictable inbox placement and isolating deliverability performance from other ESP users, especially crucial for high-volume, consistent campaigns.
- DMARC Policy & Alignment Nuances: While DMARC's direct impact on delivery can be marginal, it provides vital policy and reporting capabilities. However, its full effectiveness, particularly for stronger policies, hinges on proper domain-aligned DKIM support from the ESP, making a 'p=none' policy advisable without such alignment.
- IP Strategy Influences Control: The choice between dedicated and shared IPs determines the level of direct control over sending reputation, with dedicated IPs offering exclusivity for consistent deliverability, versus shared IPs leveraging a collective reputation which can be suitable for lower volumes but carries collective risk.
- Content & ISP Analysis are Crucial: Regardless of technical setup, message content, engagement metrics, and pinpointing specific ISPs where deliverability issues occur are fundamental for diagnosing and resolving spam placement, often indicating content or engagement as the root cause if authentication is correctly configured.
Key considerations
- Mandatory Authentication Configuration: It is imperative to correctly set up SPF, DKIM, and DMARC with your ESP, as these are non-negotiable for proving legitimacy and preventing emails from being flagged as spam or phishing.
- Strategic IP Selection: Choose your IP type wisely, as a dedicated IP is key for high-volume senders seeking exclusive control over their reputation and consistent performance, while shared IPs can suffice for lower volumes, leveraging the ESP's overall reputation.
- DMARC Implementation with Caution: When implementing DMARC, proceed with caution beyond a 'p=none' policy unless your ESP fully supports domain-aligned DKIM, as a misalignment can inadvertently impact deliverability.
- Holistic Deliverability Management: Effective deliverability involves a multi-faceted approach, combining robust authentication and appropriate IP strategy with engaging content, proactive monitoring of recipient engagement, and targeted troubleshooting for specific ISPs to ensure optimal inbox placement.
Marketer view
Marketer from Email Geeks explains that for DMARC, an ESP primarily needs to support SPF and DKIM, though DMARC's effect on delivery might be marginal. He advises that while SPF is easy to add, DKIM might not be possible if the ESP signs on their own domain. He also suggests that adding DMARC without domain-aligned DKIM is not advisable (beyond a p=none policy). He recommends focusing on typical deliverability factors like message content, links, and identifying specific ISPs where emails land in spam, noting that if SPF is set up correctly, content is more likely the issue than the IP.
27 May 2023 - Email Geeks
Marketer view
Email marketer from ActiveCampaign Blog shares that SPF, DKIM, and DMARC are vital for establishing a trustworthy sender reputation, which is directly tied to email deliverability. When sending through a third-party ESP, these authentication methods allow the ESP's infrastructure to send mail on behalf of your domain without being flagged as fraudulent, significantly boosting inbox placement.
3 Jun 2022 - ActiveCampaign Blog
What the experts say
5 expert opinions
When working with a third-party Email Service Provider (ESP), ensuring optimal deliverability hinges on a strategic blend of robust email authentication and an informed approach to IP address selection. Protocols like SPF, DKIM, and DMARC are fundamental; they serve to authenticate your domain, verify message integrity, and instruct receiving servers on how to handle unauthenticated mail, collectively building trust and significantly reducing the likelihood of emails being flagged as spam. While ESPs typically facilitate the setup of these crucial records, their proper configuration is paramount. Concurrently, the choice of IP address influences your sending reputation. A dedicated IP provides a sender with complete autonomy over their reputation, making it highly beneficial for high-volume senders who desire predictable performance and isolation from other users. However, for certain environments like Gmail, a dedicated IP might not always be advantageous, and its effectiveness is heavily reliant on a careful warm-up process. Ultimately, effective troubleshooting of deliverability issues also requires precisely identifying where emails are failing, as solutions vary significantly depending on the recipient's email environment.
Key opinions
- Auth Protocols Build Trust: SPF, DKIM, and DMARC are critical for validating sender identity and message authenticity, which is essential for deliverability through an ESP and for preventing emails from being marked as spam.
- Dedicated IP Offers Reputation Control: A dedicated IP provides complete control over the sender's reputation, making it highly advantageous for high-volume senders to ensure consistent deliverability uninfluenced by others.
- DMARC Enhances Policy & Reporting: DMARC adds a crucial layer for setting policies on unauthenticated emails and provides reporting capabilities, collectively improving sender trustworthiness with receiving servers.
- Dedicated IP Nuances for Deliverability: While offering control, a dedicated IP may not always improve deliverability, especially for services like Gmail, where a proper warm-up is crucial to avoid initial hindering of delivery.
- Targeted Troubleshooting is Key: Accurately identifying whether emails are going to spam in specific environments, for example, Gmail or private domains, is the first critical step for effective deliverability troubleshooting, as solutions are context-dependent.
Key considerations
- Implement Core Authentication: Ensure SPF, DKIM, and DMARC records are correctly configured with your ESP, as these foundational measures establish sender legitimacy and are vital for avoiding spam filters.
- Evaluate Dedicated IP Suitability: Assess whether a dedicated IP aligns with your sending volume and goals. While it offers reputation control for high-volume senders, understand that it requires careful warm-up and might not offer immediate advantages for all recipient types.
- Pinpoint Deliverability Issues: When troubleshooting, precisely determine where emails are being sent to spam. This diagnostic clarity is essential because the strategies for resolving deliverability vary significantly depending on the specific recipient domain or ISP.
Expert view
Expert from Email Geeks explains that a dedicated IP address is unlikely to improve email deliverability in this scenario, especially for Gmail, where it could even hinder delivery during warm-up. She stresses that the critical first step in troubleshooting deliverability issues is to accurately identify where emails are going to spam (e.g., Gmail versus private or business domains), as the solution approach differs significantly based on the recipient's email environment.
19 Feb 2024 - Email Geeks
Expert view
Expert from Spam Resource explains that SPF, DKIM, and DMARC are crucial for email deliverability when using a third-party ESP. SPF authenticates authorized sending servers, DKIM verifies message integrity and sender authenticity, and DMARC provides a policy layer to instruct receiving servers on how to handle unauthenticated emails and provides reporting. ESPs often assist in configuring these records to ensure proper authentication and enhance trust, which directly impacts deliverability.
9 Jan 2024 - Spam Resource
What the documentation says
4 technical articles
For email marketers utilizing a third-party Email Service Provider, the effectiveness of email delivery is profoundly influenced by proper domain authentication. SPF, DKIM, and DMARC stand as crucial protocols that collectively verify your sending identity and authorize your ESP to dispatch emails on your behalf. These measures are indispensable for building trust with recipient mail servers, preventing your legitimate communications from being misidentified as spam or phishing attempts, and ultimately ensuring they reach the intended inbox. Successfully configuring these DNS records, often guided by your ESP, is a non-negotiable step towards optimizing deliverability rates.
Key findings
- Auth Protocols Verify Legitimacy: SPF, DKIM, and DMARC are crucial email authentication protocols that enable recipient servers to verify your domain's legitimacy and authorize your third-party ESP to send emails on your behalf, significantly improving deliverability.
- Prevention of Spam & Spoofing: These protocols are critical for preventing your emails from being flagged as spam, phishing, or spoofing attempts, directly building trust with Internet Service Providers (ISPs).
- Directly Impacts Inbox Placement: Proper configuration of SPF, DKIM, and DMARC dramatically increases the likelihood that your emails will land in the recipient's inbox rather than being diverted to spam folders.
- ESPs Facilitate Configuration: Third-party ESPs like Mailchimp, SendGrid, and Postmark emphasize and provide documentation for configuring these essential DNS records, highlighting their importance for client deliverability.
Key considerations
- Essential DNS Configuration: Correctly setting up SPF, DKIM, and DMARC DNS records is vital for any domain using a third-party ESP, as these are the foundational steps for email authentication and improved deliverability.
- Collaborate with ESP: Leverage your third-party ESP's documentation and support for accurate configuration of these authentication protocols, as their guidance is crucial for proper setup and optimal deliverability impact.
- Prioritize Sender Trust: Recognize that proper SPF, DKIM, and DMARC implementation directly contributes to establishing a trustworthy sender identity with recipient servers, which is paramount for consistent inbox placement and avoiding spam folders.
Technical article
Documentation from Mailchimp Knowledge Base explains that when using a third-party ESP like Mailchimp, configuring SPF and DKIM allows recipients' email servers to verify that Mailchimp is authorized to send emails on your behalf, significantly improving deliverability and preventing your emails from being flagged as spam.
28 Apr 2022 - Mailchimp Knowledge Base
Technical article
Documentation from SendGrid Docs states that SPF, DKIM, and DMARC are crucial email authentication protocols that verify a sender's identity, reduce spam, and build trust with ISPs. When using a third-party ESP, these protocols ensure that the ESP's sending infrastructure is properly authorized for your domain, which is fundamental for good deliverability and avoiding spoofing.
14 Jul 2021 - SendGrid Docs
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