Summary
Experts and documentation sources consistently highlight that an IP address on a blocklist significantly degrades email deliverability and open rates. This results from emails being rejected, directed to spam folders, or outright blocked by ISPs and email providers. IP reputation is a crucial filtering factor, and blocklisting leads to its deterioration. The extent of the impact depends on the connection between the IP and the domain, warranting a domain-specific investigation. Shared IPs amplify the problem, affecting all users on that IP regardless of sending practices. Proactive monitoring and maintenance of a positive sender reputation are critical to avoid these issues.
Key findings
- Deliverability Impact: Blocklisted IPs cause email rejection, spam folder placement, or complete blocking.
- Open Rate Reduction: Lower deliverability directly results in decreased email open rates.
- Reputation Damage: Blocklisting damages IP and sender reputation, a key filtering factor for ISPs.
- Shared IP Risk: Shared IPs pose a risk; one user's actions can lead to blocklisting for all users.
- ISP Filtering: ISPs use IP reputation, influenced by blocklists, to filter email.
- Domain Specificity: The impact of an IP on a blocklist can vary depending on its relationship with the domain.
Key considerations
- Blocklist Monitoring: Regularly monitor your IP address on various blocklists.
- Sender Reputation Management: Prioritize maintaining a good sender reputation through proper email practices.
- Domain Investigation: Investigate the domain and its MX records when troubleshooting deliverability problems.
- Email Authentication: Implement email authentication protocols (SPF, DKIM, DMARC) to improve deliverability.
- Swift Action: If blocklisted, take immediate action to identify the cause and request delisting.
- Monitor Email Programs: Use tools such as Google Postmaster Tools and Microsoft SNDS to understand deliverability.
What email marketers say
10 marketer opinions
Multiple email marketing experts agree that an IP address on a blocklist significantly harms email deliverability and open rates. Blocklisting leads to emails being rejected, sent to spam folders, or blocked entirely by ISPs. This happens because ISPs and email providers use IP reputation, heavily influenced by blocklist status, to filter spam. Shared IPs exacerbate the problem, affecting all users on that IP, regardless of their sending practices. Monitoring IP addresses for blocklisting is crucial for maintaining a healthy sender reputation and ensuring emails reach their intended recipients.
Key opinions
- Deliverability Impact: Blocklisted IPs result in reduced email deliverability as ISPs reject or filter emails.
- Open Rate Reduction: Lower deliverability directly translates to decreased email open rates because fewer emails reach inboxes.
- Reputation Damage: Being on a blocklist damages IP reputation, a key factor in email filtering by ISPs.
- Shared IP Risk: Shared IPs pose a risk, as one user's actions can lead to blocklisting and affect all users.
- Spam Folder Placement: Even if not blocked, blocklisted IPs often result in emails landing in the spam folder, hurting open rates.
Key considerations
- Blocklist Monitoring: Regularly monitor your IP address on various blocklists to identify and address issues promptly.
- Sender Reputation: Maintain a good sender reputation by following email best practices and avoiding spam triggers.
- Shared IP Awareness: If using a shared IP, understand the risks and monitor the IP's reputation closely.
- Proactive Measures: Implement email authentication protocols (SPF, DKIM, DMARC) to improve deliverability and sender reputation.
- Swift Action: If blocklisted, take immediate steps to identify the cause and request delisting from the relevant blocklists.
Marketer view
Email marketer from Mailjet explains that a poor IP reputation, often resulting from being on a blocklist, directly reduces the chances of your emails reaching the inbox. ISPs use IP reputation as a key factor in filtering spam, so a blocked IP can lead to drastically lower open rates.
23 Feb 2023 - Mailjet
Marketer view
Email marketer from EasyDMARC explains that blacklisted IPs can cause a multitude of problems, including the recipient server blocking your emails, or routing them to the spam folder. This has a profound effect on email deliverability.
1 Jul 2022 - EasyDMARC
What the experts say
4 expert opinions
Experts agree that an IP address on a blocklist can negatively impact domain reputation and email open rates. The extent of the impact depends on the connection between the IP address and the domain, necessitating a domain-specific investigation. Monitoring blocklists is crucial, as a listed IP will likely impact email open rates. IP reputation is a key factor in how email providers filter email, with poor reputation due to blocklists causing deliverability problems and reduced open rates.
Key opinions
- Impact on Reputation: IP address blocklisting can negatively impact domain reputation.
- Reduced Open Rates: A listed IP can lead to decreased email open rates.
- Importance of Monitoring: Regular monitoring of blocklists is essential to identify potential issues.
- Key Filtering Factor: IP reputation is a primary factor used by email providers to filter email.
- Domain-Specific Analysis: Analyzing the specific domain and its connection to the IP is needed for accurate diagnosis.
Key considerations
- Domain Investigation: Investigate the specific domain to determine the extent of the IP address's impact.
- Regular Monitoring: Implement a system for regular blocklist monitoring.
- Reputation Management: Prioritize maintaining a good IP reputation to avoid blocklisting.
- Deliverability Best Practices: Adhere to email deliverability best practices to improve inbox placement.
- MXToolbox Assessment: Utilize tools like MXToolbox to assess domain and IP health.
Expert view
Expert from Email Geeks explains that whether the IP address is affecting the customer's domain reputation depends on the connection between the IP address and the domain.
11 Jul 2021 - Email Geeks
Expert view
Expert from Spam Resource explains that monitoring blocklists is crucial. If your IP is listed, your email open rates will be impacted.
1 Sep 2021 - Spam Resource
What the documentation says
4 technical articles
Email deliverability documentation from Spamhaus, Google Postmaster Tools, Microsoft SNDS, and Cisco Talos confirms that an IP address on a blocklist significantly harms email deliverability and open rates. Blocklisting leads to email rejection, spam folder placement, or complete blocking by ISPs and email providers. IP reputation, a key factor in sender evaluation, is negatively impacted, resulting in reduced or non-existent open rates, especially for users of major email platforms like Gmail, Outlook.com, and Hotmail.
Key findings
- Deliverability Impact: Blocklisted IPs cause email rejection, spam filtering, or complete blocking.
- Reduced Open Rates: Blocklisting leads to reduced or non-existent open rates.
- IP Reputation Key: IP reputation is a crucial factor in email deliverability decisions by major providers.
- Gmail Impact: Blocklisting severely affects deliverability and open rates for Gmail users.
- Outlook/Hotmail Impact: Blocklisting negatively affects deliverability and open rates for Outlook.com and Hotmail users.
Key considerations
- Blocklist Monitoring: Regularly monitor IP addresses on blocklists.
- SBRS Assessment: Understand your SenderBase Reputation System (SBRS) score.
- Sender Reputation: Prioritize maintaining a positive sender reputation.
- Google Postmaster Tools: Utilize Google Postmaster Tools to monitor Gmail deliverability.
- Microsoft SNDS: Leverage Microsoft SNDS to assess deliverability to Outlook.com and Hotmail users.
Technical article
Documentation from Microsoft SNDS details that it provides data about your IP reputation and potential issues affecting deliverability to Outlook.com and Hotmail users. A blocklisted IP will cause delivery failures or spam filtering, severely impacting open rates.
23 Mar 2022 - Microsoft
Technical article
Documentation from Google Postmaster Tools explains that Google uses sender reputation, heavily influenced by IP reputation, to determine whether to deliver emails to the inbox, spam folder, or block them entirely. Poor reputation due to blocklisting can result in reduced or non-existent open rates for Gmail users.
29 Jun 2024 - Google
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