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What is a shared IP address and how does it affect email deliverability?
Summary
A shared IP address is used by multiple senders, offering cost-effectiveness, easier management, and scalability. However, deliverability is significantly influenced by the IP's reputation, which is tied to the sending practices of all users sharing it. Poor sending habits from one user can negatively affect deliverability for everyone. While IP reputation has become less critical since 2015, it still matters. New senders on shared IPs often require a 'warm-up' period, gradually increasing sending volume to build a positive reputation. Monitoring your sending reputation, using permission-based lists, sending relevant content, and authenticating emails are crucial for improving deliverability on a shared IP. Services like Amazon SES and SparkPost actively manage IP reputation to mitigate risks.

Key findings

  • Shared Resource: A shared IP is used by multiple senders, offering cost advantages.
  • Reputation Dependence: Deliverability is highly dependent on the IP's reputation, influenced by all users.
  • Negative Impact Potential: Poor sending practices by one user can negatively impact others.
  • Warm-up Necessity: New senders often need to warm up the IP to establish a positive reputation.
  • Proactive Management: Monitoring and maintaining good sending habits are crucial.

Key considerations

  • Sending Practices: Adhere to email sending best practices to avoid negatively impacting IP reputation.
  • Reputation Monitoring: Regularly monitor your sending reputation to address issues promptly.
  • List Hygiene: Maintain a clean, permission-based list to minimize spam complaints.
  • Authentication: Implement email authentication (SPF, DKIM, DMARC) to improve sender credibility.
  • Content Relevance: Send relevant and engaging content to avoid being marked as spam.
  • Warm-up Strategy: Plan a gradual warm-up strategy when starting with a shared IP.
What email marketers say
8 marketer opinions
A shared IP address is used by multiple senders for sending email. While cost-effective and easier to manage, deliverability is highly dependent on the IP's reputation, which is influenced by the sending practices of all users sharing the IP. Poor sending habits from one user can negatively affect deliverability for all. Senders using shared IPs often need to 'warm-up' the IP and must closely monitor their sending reputation. Best practices for shared IPs include using permission-based lists, sending relevant content, and email authentication. Advantages include cost-effectiveness, easier management, immediate deliverability, and scalability.

Key opinions

  • Reputation Matters: Deliverability on a shared IP is directly tied to the reputation of the IP address, influenced by all senders using it.
  • Negative Impact: Poor sending practices from one user can negatively impact the deliverability of all users sharing the IP.
  • Warm-up Required: New senders on shared IPs often need to gradually increase sending volume to build a positive reputation.
  • Monitoring is Key: Continuously monitoring sending reputation is crucial for identifying and addressing deliverability issues.
  • Cost-Effective: Shared IPs are a cost-effective option compared to dedicated IPs.

Key considerations

  • Sending Practices: Ensure your sending practices are compliant with email best practices, as your deliverability depends on the actions of others.
  • Reputation Monitoring: Regularly monitor your sending reputation and take action to address any issues promptly.
  • List Hygiene: Maintain a clean, permission-based email list to minimize spam complaints and improve engagement.
  • Authentication: Implement email authentication protocols (SPF, DKIM, DMARC) to improve sender credibility.
  • Content Relevance: Send relevant and engaging content to avoid being marked as spam and to encourage positive engagement.
Marketer view
Email marketer from Litmus explains that with shared IPs your deliverability can be influenced by the sending practices of others. You can inherit their reputation problems, even if you follow email best practices.
30 Apr 2022 - Litmus
Marketer view
Email marketer from Campaign Monitor explains that shared IPs have advantages that include; cost effectiveness, easier management, immediate deliverability and scalability. They also discuss the disadvantages of deliverability with shared IPs
21 Jun 2022 - Campaign Monitor
What the experts say
4 expert opinions
A shared IP address is an IP used by multiple organizations or senders, as is common with ESPs like Mailchimp and AmazonSES, and services like G Suite. Historically, shared IPs posed deliverability risks due to the potential for other users' poor sending practices to negatively impact the IP's reputation and lead to blocking. While IP reputation has become less critical since 2015, shared IPs still require careful management. New senders using shared IPs typically need to warm up the IP by gradually increasing sending volume to establish a positive reputation and avoid spam filters.

Key opinions

  • Definition: A shared IP address is used by multiple organizations or senders.
  • Historical Risk: Historically, poor sending practices of other users on a shared IP could negatively impact deliverability.
  • Less Critical Now: IP reputation is less crucial than before, especially at consumer mailbox providers since 2015.
  • Warm-up Required: New senders on shared IPs typically need to warm up the IP address.

Key considerations

  • Monitor Reputation: Continuously monitor the IP reputation to identify and address issues promptly, even if less critical than before.
  • Warm-up Process: Follow a warm-up process when starting to send from a shared IP to build a positive reputation gradually.
  • Sending Practices: Adhere to email sending best practices, as your deliverability can still be influenced by other users on the shared IP.
Expert view
Expert from Email Geeks shares that in the past, blocking was based on IP addresses, and shared IPs could be problematic. However, since around 2015, IP reputation has become less crucial, particularly at consumer mailbox providers, making shared IPs less of a concern.
4 May 2023 - Email Geeks
Expert view
Expert from Word to the Wise shares that shared IPs are used by multiple senders and performance depends on the IP reputation. If other senders have poor sending practices, it can affect your email delivery even with good practices.
20 Oct 2022 - Word to the Wise
What the documentation says
4 technical articles
Shared IP addresses, as used by services like Amazon SES, SparkPost, Google, and Digital Ocean, are IPs utilized by multiple senders. Documentation highlights that deliverability is affected by the actions of all users sharing the IP. These providers actively monitor sending practices and manage IP reputation to minimize risks and maintain a good IP reputation. Good sending habits are essential for all users on a shared IP, and monitoring one's sending reputation is crucial.

Key findings

  • Shared Use: Shared IP addresses are used by multiple senders/users.
  • Impact on Deliverability: Deliverability is directly influenced by the sending behavior of all users on the shared IP.
  • Reputation Management: Providers actively manage IP reputation to mitigate risks associated with shared IPs.
  • Cost-Effective: Shared IPs offer a cost-effective solution for sending emails.

Key considerations

  • Good Sending Habits: Adhere to good sending practices to maintain a positive sending reputation and avoid negatively impacting others.
  • Reputation Monitoring: Monitor your sending reputation regularly to identify and address any issues promptly.
  • Provider's Role: Understand and leverage the reputation management practices of your email service provider.
  • Strategic Choice: Consider the influence on deliverability when determining your IP strategy.
Technical article
Documentation from Amazon Web Services explains that Amazon SES uses shared IP addresses for sending emails, where multiple users share the same IP. They actively monitor sending practices to maintain a good reputation for these IPs, minimizing negative impacts on deliverability.
12 May 2024 - Amazon Web Services
Technical article
Documentation from Digital Ocean explains that Shared IPs are a cost-effective way to send email, but they come with risks. They elaborate on the need for senders to practice good sending habits and monitor their reputation, as it reflects on all users sharing the IP.
7 Jun 2023 - Digital Ocean
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