What is the best IP network configuration and email volume strategy for email service providers to avoid deliverability issues?
Summary
What email marketers say7Marketer opinions
Email marketer from StackOverflow explains that when warming up new IPs, start with very small sending volumes (e.g., a few hundred emails per day) and gradually increase it. Monitor the IPs in blocklist services and ensure you aren't appearing on any blacklists.
Email marketer from SendGrid explains list segmentation helps to improve deliverability by sending relevant content to specific audiences. This reduces the likelihood of recipients marking emails as spam.
Email marketer from SuperUser.com explains that it's better to use a small range of IPs initially and grow as required. Starting with a /24 range and then expanding if needed is a sensible approach.
Email marketer from Mailjet shares that maintaining a good sender reputation is key. This involves sending consistent volume, having low complaint rates, and authenticating emails with SPF, DKIM, and DMARC.
Email marketer from GlockApps shares the importance of monitoring and managing complaint rates. High complaint rates negatively impact sender reputation. Clean your email lists regularly to remove disengaged subscribers.
Email marketer from Reddit answers that using separate IP pools for transactional and marketing emails is a good strategy. If the marketing emails get a lot of spam complaints it wont affect transactional emails.
Email marketer from EmailDeliverabilityForum.com shares that using dedicated IPs gives you more control over your sender reputation, it can improve deliverability. Shared IPs are fine if you are just getting started or don't send a lot of mail, but dedicated IPs are better for ESPs with high volumes.
What the experts say8Expert opinions
Expert from Email Geeks answers that for sending 500k emails daily to Yahoo/AOL, one or two IPs should be used, not 10 or 50.
Expert from Word to the Wise explains that engagement-based filtering at mailbox providers greatly affects deliverability. Maintaining good engagement with your audience and removing unengaged subscribers helps improve placement in inboxes rather than spam folders.
Expert from Spam Resource recommends utilizing feedback loops to track complaints. They share that using feedback loops you'll know which recipients marked your messages as spam. Addressing these complaints is vital for maintaining a good sender reputation.
Expert from Email Geeks explains that a single /22 IP range is better than 32 /27s for ESPs because it reduces maintenance overhead. A single /22 is marginally better than four /24s because less likely to break something.
Expert from Email Geeks explains that being in back off mode means the sender has been blocked for sending unwanted mail and that stopping sending unwanted mail is the solution.
Expert from Email Geeks explains that using multiple scattered /27 IP ranges can make traffic look like a snowshoe spammer.
Expert from Spam Resource emphasizes that proper email authentication (SPF, DKIM, DMARC) and correct infrastructure setup are critical. They explain that failing to authenticate your email properly will result in deliverability issues, especially with major mailbox providers.
Expert from Email Geeks explains complaint rates may be about the content of the message, the links in the message or the sending domains and that fixing the reason why people are reporting mail as unwanted is key. They also stated Yahoo isn’t going to accept mail any faster if sender tries to snowshoe.
What the documentation says4Technical articles
Documentation from Microsoft explains that it's very important to make sure reverse DNS entries match the sending domain and that forward confirmed reverse DNS is used. Make sure the hostname in the banner matches what the reverse DNS shows or your emails will be blocked.
Documentation from Google Postmaster Tools explains the value of using Google Postmaster Tools to monitor IP reputation and domain reputation. This provides insights into deliverability issues with Gmail users.
Documentation from RFC explains how to set up SPF (Sender Policy Framework) records correctly. SPF records authorize specific IP addresses to send emails on behalf of a domain, which helps prevent spoofing and improves deliverability.
Documentation from SparkPost explains that a gradual IP warmup is crucial for new IP addresses. Starting with low volumes and gradually increasing it over several weeks helps build a positive reputation with ISPs.