How can I convince an email network owner to whitelist my IPs to reduce bounces?
Michael Ko
Co-founder & CEO, Suped
Published 6 Jun 2025
Updated 15 Aug 2025
7 min read
Dealing with email bounces can be a frustrating experience, especially when it seems like your legitimate emails are being rejected for no clear reason. You might hear about IP whitelisting as a solution, a concept where an email network owner (like an ISP or a large company) specifically permits emails from your IP addresses to bypass some of their spam filters. It sounds like the silver bullet, doesn't it?
However, in today's email landscape, direct IP whitelisting requests are rarely granted by major email providers. The industry has largely moved away from static allowlists towards dynamic, reputation-based filtering systems. This means that while some smaller, local networks might still engage in it, larger players rely heavily on your ongoing sending behavior and established trust, rather than a one-time approval.
My experience has shown that focusing on your overall sender reputation and adherence to best practices is far more effective than chasing a whitelist that most networks simply won't provide. If you're seeing high bounce rates, it's crucial to first understand the root cause before attempting to ask for an IP whitelist (or blocklist removal).
Diagnosing the bounce issue
The first step in addressing any email deliverability issue, including high bounces, is to accurately diagnose the problem. A generic soft bounce can hide many different underlying issues. You need to get to the specific bounce codes and messages from the receiving server. This information is usually found in your mail server logs or the bounce reports provided by your email service provider (ESP).
For instance, a 550 5.1.1 Recipient address rejected: User unknown indicates that the email address simply doesn't exist, as was the case in one user's experience when an email network migrated its database. This is a hard bounce, and no amount of whitelisting will fix it. The only solution is to remove that address from your list.
If the bounce message explicitly states your IP is listed on a specific blocklist (or blacklist), like Spamhaus ZEN, then you've identified a clear problem. However, as noted in the Reddit discussion Whitelisting email/domains, whitelisting is not a common practice. Instead, you need to work on getting your IP removed from that blocklist by addressing the underlying cause of the listing. This often involves collaborating closely with your ESP, especially if you're sending from shared IP ranges. For more information on blocklists, see an in-depth guide to email blocklists.
Example Bounce Message: Recipient Unknown
550 5.1.1 <recipient@domain.com>: Recipient address rejected: User unknown in relay recipient table
Hard bounces
Meaning: Permanent delivery failure, such as invalid email address or domain.
Action: Immediately remove these addresses from your mailing list to protect your sender reputation.
Impact: High hard bounce rates severely damage your sender reputation and can lead to blacklisting (or blocklisting).
Soft bounces
Meaning: Temporary delivery failure, such as full inbox, server downtime, or large message size.
Action: Most ESPs will retry sending. If persistent, consider removing.
Impact: Can indicate temporary issues but high volumes can still negatively affect reputation.
Prioritizing sender reputation over whitelisting
Instead of direct whitelisting, your primary focus should be on building and maintaining a strong sender reputation. This is what truly convinces email network owners that your mail is legitimate and wanted. Reputation is built over time through consistent, positive sending behavior.
The core principle is to send wanted email to engaged recipients. This means rigorous list hygiene to eliminate invalid or inactive addresses, ensuring your subscribers genuinely opted in, and segmenting your audience to send relevant content. High engagement (opens, clicks, replies) signals to ISPs that your mail is valued, while low engagement or high complaints will swiftly damage your standing. You can find more comprehensive advice on this in our guide on how to improve your email reputation and deliverability.
Proper email authentication is also non-negotiable. Setting up SPF, DKIM, and DMARC records correctly proves that your emails are legitimately coming from your domain and haven't been tampered with. This is a fundamental trust signal for all email network owners. Missing or misconfigured authentication can lead to emails being marked as spam or rejected outright. Learn more about DMARC, SPF, and DKIM.
Good sending practices
Bad sending practices
List hygiene: Regularly cleaning your list of invalid, inactive, or bouncing addresses.
List decay: Sending to old, unengaged, or purchased lists.
Engagement: Sending relevant content that encourages opens and clicks.
Spam complaints: Receiving a high volume of 'mark as spam' reports.
Authentication: Properly configured SPF, DKIM, and DMARC records.
Malware/phishing: Sending malicious content or being associated with phishing attacks.
Engaging with network owners
When you do need to communicate with an email network owner (often referred to as a postmaster or ISP), approach the conversation from a problem-solving perspective, not just a request for whitelisting. Begin by providing all relevant data about the issue. This includes bounce messages, timestamps, sending IPs, sender and recipient addresses, and specific campaigns. The more data you provide, the better equipped they will be to assist you. This is echoed in Postmark's guide on ISP blocks, which emphasizes reaching out to recipients or postmasters.
If a network owner explicitly states they cannot whitelist your IPs (or IP range, as was discussed in the Mailchimp thread), respect their policy. Pushback can often be counterproductive. Instead, ask for guidance on what metrics or improvements they look for in senders. Their willingness to offer support for specific issues rather than blanket whitelisting suggests they prefer an ongoing, data-driven approach. Your goal is to show a commitment to good sending practices. This often means working with your ESP to resolve any blocklist issues on shared IPs, as large ranges are managed at their end. For dealing with unresponsive postmasters, consider how to resolve email blacklisting when an ISP postmaster is unresponsive.
If the issue is related to IP blocklisting, as was clarified in the bounce example, then the conversation shifts from whitelisting to de-listing (or removal from a blacklist). This typically involves addressing the cause of the listing (e.g., spam complaints, sending to old lists) and then following the specific removal process of the blocklist provider. Once removed, maintaining a clean sending record is paramount to avoid future listings. You can use a blocklist checker to monitor your status.
Tips for communicating with network owners
Be detailed: Provide all requested information, including headers and logs.
Be patient: Resolution can take time, especially with larger networks.
Demonstrate action: Outline steps you're taking to improve sending practices.
A sustainable approach to deliverability
Ultimately, convincing an email network owner to whitelist your IPs is often about demonstrating a consistently positive sending reputation and a commitment to best practices. If a network owner expresses an unwillingness to whitelist, it's typically because their systems are designed to trust good senders based on their behavior, not explicit approvals. The focus should be on becoming that trusted sender. This involves proactive list management, strong authentication, and monitoring your email deliverability metrics. If issues persist, such as with Yahoo or AOL, investigate specific issues using bounce reports or Google's support resources.
Remember, the goal isn't just to get an IP whitelisted; it's to ensure your emails reach the inbox reliably. This requires ongoing vigilance and adaptation to evolving email security measures. By focusing on your sender reputation, you build a sustainable path to strong deliverability.
Views from the trenches
Best practices
Maintain pristine email lists, regularly removing inactive or invalid addresses.
Implement strong email authentication: SPF, DKIM, and DMARC.
Monitor your sender reputation using tools like Google Postmaster Tools.
Segment your audience and send relevant, engaging content.
Ensure easy unsubscribe options are clearly visible.
Common pitfalls
Purchasing or scraping email lists, leading to high bounce and complaint rates.
Ignoring bounce messages and continuing to send to invalid addresses.
Assuming whitelisting is a universal solution for deliverability issues.
Sending inconsistent email volumes, which can raise suspicion.
Failing to monitor blocklists (or blacklists) for your sending IPs and domains.
Expert tips
Focus on long-term relationship building with ISPs through consistent good sending.
Understand that most modern systems prioritize sender behavior over static whitelists.
If using an ESP, ensure they are actively managing their IP reputation.
Don't hesitate to engage with postmasters, but lead with data and solutions.
Recognize that a
Expert view
Expert from Email Geeks says that getting IPs whitelisted by email networks is increasingly rare, as most systems now prioritize operational data and sender behavior over manual requests.
2020-03-16 - Email Geeks
Expert view
Expert from Email Geeks says that sending good mail to engaged recipients at consistent volumes is usually sufficient to achieve reliable email delivery without explicit whitelisting.
Spamhaus ZEN, then you've identified a clear problem. However, as noted in the Reddit discussion Whitelisting email/domains, whitelisting is not a common practice. Instead, you need to work on getting your IP removed from that blocklist by addressing the underlying cause of the listing. This often involves collaborating closely with your ESP, especially if you're sending from shared IP ranges. For more information on blocklists, see an in-depth guide to email blocklists.
Mailchimp thread), respect their policy. Pushback can often be counterproductive. Instead, ask for guidance on what metrics or improvements they look for in senders. Their willingness to offer support for specific issues rather than blanket whitelisting suggests they prefer an ongoing, data-driven approach. Your goal is to show a commitment to good sending practices. This often means working with your ESP to resolve any blocklist issues on shared IPs, as large ranges are managed at their end. For dealing with unresponsive postmasters, consider how to resolve email blacklisting when an ISP postmaster is unresponsive.
Yahoo or 
AOL, investigate specific issues using bounce reports or Google's support resources.
