Summary
Sender reputation is a complex metric determined by various factors, including sending domain, IP address, message content, authentication, list quality, and engagement. Domain reputation is crucial and, to some extent, independent of IP, though IP reputation remains vital for Gmail. Subdomain reputation can affect the parent domain, and Google considers broader data points. Proper domain authentication (SPF, DKIM, DMARC) is essential for proving sender identity and building trust. Engagement metrics like opens, clicks, and low complaint rates signal a positive reputation, while spam traps, poor content, and high complaints negatively impact it. New IPs require warming, and maintaining a clean list is paramount. Third-party senders also pose reputation risks.
Key findings
- Domain Authority: Domain reputation heavily influences deliverability, often independent of IP, and is based on header and body domains.
- IP Importance: IP address reputation is key, especially for Gmail, where poor reputation leads to spam or blocks.
- Subdomain Interplay: Subdomain reputation impacts parent domain, influencing overall deliverability based on ISP and reputation services.
- Email Authentication (SPF, DKIM, DMARC): Essential for trust, proving sender identity, and preventing spoofing to maintain a positive sender reputation.
- Engagement is Crucial: High open rates, click-through rates, and low complaints indicate positive reputation and better deliverability.
- List Hygiene is Vital: Maintaining clean lists by removing inactive users and avoiding spam traps reduces complaints and improves engagement.
- Content Matters: Spam trigger words, poor formatting, and deceptive subject lines decrease deliverability and harm sender reputation.
Key considerations
- Prioritize Domain Health: Actively manage and monitor domain reputation to ensure consistently positive sending habits.
- Authenticate Everything: Implement and regularly check SPF, DKIM, and DMARC records to verify sender identity and boost trust.
- Optimize for Engagement: Create engaging, relevant content that encourages opens, clicks, and responses.
- Segment and Clean Lists: Segment email lists, regularly remove inactive users, and avoid spam traps to maintain engagement and sender reputation.
- Monitor Complaint Rates: Closely monitor and address high complaint rates to identify and solve underlying issues, preventing further reputational harm.
- Be Wary of Third Parties: Thoroughly vet and regularly monitor any third-party sending methods to protect your sender reputation.
- Warm-Up New IPs: If sending from a new IP, gradually increase sending volume to establish a positive reputation with ISPs.
What email marketers say
11 marketer opinions
Sender reputation is influenced by multiple factors, including the sending domain, IP address, and message content. A good domain reputation helps offset IP reputation issues. Sending practices such as authenticating your domain (SPF, DKIM, DMARC), warming up new IP addresses, maintaining clean email lists, and avoiding spam trigger words are crucial. Engagement metrics like open and click-through rates are also critical indicators of sender reputation. Poor practices like sending to spam traps, using deceptive content, or having high complaint rates negatively impact deliverability.
Key opinions
- Domain Reputation: A reputable sending domain is crucial, and domain authentication (SPF, DKIM, DMARC) is essential for trust with ISPs.
- IP Warming: New IP addresses require a warming period to avoid triggering spam filters.
- Message Content: Avoid spam trigger words, use proper HTML formatting, and personalize content to improve engagement.
- List Hygiene: Maintaining a clean email list by removing inactive subscribers and spam traps is important.
- Engagement Metrics: High open rates, click-through rates, and low complaint rates signal a positive reputation.
- Subdomain Reputation: Poor subdomain reputation can negatively affect parent domain reputation.
Key considerations
- Domain Authentication: Ensure SPF, DKIM, and DMARC are properly configured to prove sender identity.
- IP Address Management: Warm up new IP addresses gradually to avoid deliverability issues.
- Content Optimization: Craft high-quality, engaging content while avoiding spam triggers and poor formatting.
- List Maintenance: Regularly clean email lists to remove inactive subscribers and spam traps.
- Reputation Monitoring: Monitor complaint rates and engagement metrics to identify and address potential issues.
- SMTP Relay Reputation: Be aware of the reputation of any SMTP relays you use, as a bad reputation can impact your deliverability.
Marketer view
Email marketer from ZeroBounce explains that spam traps are email addresses used by ISPs and blacklist providers to identify spammers. Sending email to spam traps can severely damage your sender reputation and lead to blacklisting. Regular list cleaning is essential to avoid hitting spam traps.
30 Jun 2023 - ZeroBounce
Marketer view
Email marketer from Litmus shares that properly configured SPF, DKIM, and DMARC authentication are essential for building trust with ISPs and proving that you are who you say you are. Failure to authenticate can lead to deliverability issues.
14 Apr 2023 - Litmus
What the experts say
6 expert opinions
Sending reputation is influenced by domain reputation, IP address reputation, message content, and engagement. Domain reputation persists regardless of the underlying IP and can offset a less-than-perfect IP reputation, particularly for smaller senders. Subdomain reputation can impact the root domain. Message content and list management influence engagement, impacting sender reputation. Domain authentication (SPF, DKIM, DMARC) is crucial for establishing trust and improving deliverability. Using third-party send methods can risk corporate mail reputation.
Key opinions
- Domain Reputation: Domain reputation is a primary factor, independent of IP address, and based on the domains in headers or body.
- Subdomain Impact: Subdomain reputation can affect the root domain, depending on the context (e.g., Gmail vs. Spamhaus).
- Engagement Metrics: Engagement (opens, clicks, complaints) derived from content and list practices significantly impacts reputation.
- Authentication Importance: Proper domain authentication (SPF, DKIM, DMARC) is essential for building and maintaining a positive reputation.
- Third-Party Risks: Using third-party sending methods can pose risks to corporate mail reputation.
Key considerations
- Prioritize Domain Reputation: Focus on building and maintaining a strong domain reputation through consistent and responsible sending practices.
- Implement Authentication: Ensure SPF, DKIM, and DMARC are correctly configured to verify sender identity.
- Monitor Engagement: Track engagement metrics closely to identify and address any deliverability issues promptly.
- Careful with Subdomains: Be cautious with subdomain usage, as their reputation can impact the root domain.
- Evaluate Third-Party Senders: Thoroughly vet and monitor any third-party sending methods to mitigate risks to corporate mail reputation.
Expert view
Expert from Email Geeks responds he was consulting for a client who offered a third party as a send method and he suggested that they try to move away from it. It’s almost too hard to get right and it puts your corporate mail reputation at risk if done wrong.
1 Feb 2023 - Email Geeks
Expert view
Expert from Email Geeks explains that whether a subdomain's reputation affects the root domain is complex. Domain reputation at Gmail might be based on the exact domain/subdomain, possibly even the exact domain/subdomain+dkim selector, so at that level subdomain rep is not likely to “infect” the parent domain. However, in other contexts like other ISPs or Spamhaus, if there is enough bad activity from a subdomain then it will get your domain blocked or blocklisted in a way that affects the parent domain.
19 Aug 2021 - Email Geeks
What the documentation says
5 technical articles
Sender reputation is a complex metric calculated by ISPs based on various factors. IP address reputation is crucial for Gmail deliverability. Microsoft considers sending IP, domain, authentication, list accuracy, and complaint rates. Engagement (open and click rates) are also a major factor. Correctly configured reverse DNS (rDNS) records verify the sending server's identity, while DMARC prevents spoofing and phishing, enhancing deliverability and security.
Key findings
- IP Reputation: IP address reputation significantly affects Gmail deliverability; poor reputation leads to spam or blocks.
- Microsoft's Factors: Microsoft calculates sender reputation from IP, domain, authentication, list quality, complaint rates, and more.
- Engagement Matters: High engagement (opens, clicks) improves reputation; low engagement and high complaints harm it.
- Reverse DNS (rDNS): rDNS records verify sending server identity, aiding ISP confirmation.
- DMARC Benefits: DMARC authentication prevents spoofing/phishing, improving deliverability and security.
Key considerations
- Monitor IP Reputation: Regularly check and maintain your IP address reputation for Gmail deliverability.
- Address Microsoft Factors: Address all factors considered by Microsoft to maintain a healthy sender reputation.
- Improve Engagement: Focus on improving engagement metrics (opens, clicks) to signal positive reputation.
- Configure rDNS: Ensure proper configuration of reverse DNS records for server identity verification.
- Implement DMARC: Implement DMARC authentication to prevent spoofing and phishing.
Technical article
Documentation from RFC details that a properly configured reverse DNS (rDNS) record is important for verifying the identity of your sending server. An rDNS record maps an IP address back to a domain name, helping ISPs confirm that the IP is authorized to send email for that domain.
7 Jun 2025 - RFC
Technical article
Documentation from Google Postmaster Tools explains that IP address reputation is a key factor for Gmail deliverability. A poor IP reputation can lead to emails being marked as spam or blocked.
7 Jul 2021 - Google
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