How to get Microsoft SNDS access when using an Email Service Provider?
Matthew Whittaker
Co-founder & CTO, Suped
Published 14 Jun 2025
Updated 19 Aug 2025
7 min read
Gaining access to Microsoft's Smart Network Data Services (SNDS) is crucial for any sender looking to maintain a healthy email reputation with Outlook.com and other Microsoft domains. However, the process can become complicated when you're relying on an Email Service Provider (ESP) for your sending infrastructure, especially if you're using dedicated IPs.
Many senders encounter a roadblock when requesting access to SNDS IPs managed by their ESP. Microsoft's system often presents an unexpected email address for authorization, leaving users unsure how to proceed. This guide will walk you through understanding why this happens and how to navigate the process to monitor your sending reputation effectively, even when using a third-party ESP.
Understanding SNDS and IP ownership
Microsoft SNDS is a free online service that provides detailed data on your IP's reputation, including complaint rates, spam trap hits, and blacklist (or blocklist) status for emails sent to Microsoft's email services. This information is vital for troubleshooting deliverability issues and ensuring your emails reach the inbox.
The core of the SNDS access challenge lies in IP address ownership and the associated Reverse DNS (PTR) records. When you request access for an IP address or range in SNDS, Microsoft verifies your ownership by sending an authorization email to specific addresses associated with the PTR record of that IP. These are typically addresses like abuse@yourdomain.com, postmaster@yourdomain.com, or other administrative contacts.
If you're using an Email Service Provider, even with dedicated IPs, the ESP often maintains ownership and control over the IP addresses and their corresponding PTR records. This means the authorization emails from SNDS will be sent to the ESP's administrative contacts, not directly to your company's email address. This is why you might see a strange email address listed for verification.
The challenge of authorization emails
The fundamental hurdle for senders using an ESP is that the ESP controls the IP space and the associated authorization emails. When you try to register your dedicated IPs in SNDS, Microsoft looks up the PTR record for those IPs and presents the authoritative email addresses associated with that record. These addresses belong to the ESP, not to you directly.
The authorization email issue
You will likely see an email address listed that you do not recognize or have access to, such as abuse@espdomain.com. This is because the ESP is the actual owner of the IP block. The SNDS system is designed to grant access only to the recognized owner of the IP space.
Privacy and control concerns for ESPs
ESPs may be reluctant to grant direct SNDS access to their clients. One common reason is that Microsoft's system does not provide an easy way for an ESP to revoke access once it's granted to a specific user, especially if that dedicated IP is later reassigned. This raises privacy and security concerns for the ESP, as historical sending data could remain accessible to a former user of that IP.
If you find yourself in this situation, the primary step is to reach out to your ESP's support or account management team. Clearly explain that you need to monitor your Microsoft sender reputation and require access to the SNDS data for your dedicated IPs.
While direct access might not always be possible, many ESPs will agree to pull SNDS reports for you and share them on a regular basis. This approach allows you to get the critical insights you need without the ESP having to grant direct access to their SNDS account. This is often the most practical workaround.
Strategies for getting SNDS data
Successfully obtaining SNDS data, even if it's through your ESP, is a crucial step in proactive deliverability management. Without this visibility, it's very difficult to diagnose and resolve Microsoft deliverability issues.
Direct control (self-managed)
Ownership: You directly own and manage your IP addresses and their PTR records.
SNDS access: You can register your IPs yourself and receive the authorization emails directly.
Some ESPs, particularly those offering dedicated IP addresses, may have specific processes for granting clients access to SNDS data. It's essential to understand their policy regarding this. They might require a formal request, or they may simply refuse direct access due to the reasons mentioned above. In cases where they decline, requesting regular reports is your best bet for monitoring deliverability.
For ESPs like Mailchimp, direct SNDS access for clients with dedicated IPs is generally not provided due to their inability to revoke access later. However, they can and often will provide the SNDS reports if you ask. Always confirm your ESP's specific policy and the best way to obtain this critical data.
Working with SNDS data
Once you have access to SNDS data, whether directly or via your ESP, interpreting it correctly is paramount. SNDS provides insights into various metrics that indicate the health of your sending reputation. Pay close attention to complaint rates, spam trap hits, and blocklist status. These are strong indicators of how Microsoft views your sending practices.
High complaint rates suggest that your subscribers are not engaging positively with your emails or that your list hygiene needs improvement. Spam trap hits indicate you're sending to invalid or recycled email addresses, which can severely damage your reputation. A listing on a Microsoft blocklist (or blacklist) will directly impact your deliverability, leading to messages being blocked or sent to the junk folder. This is where SNDS data becomes invaluable.
Metric
Description
Deliverability Impact
Complaint rate
The percentage of recipients marking your emails as spam.
High rates lead to lower sender reputation, increased junk folder placement.
Spam trap hits
Indicates sending to invalid or dormant addresses monitored by Microsoft.
Severe damage to sender reputation, potential IP blocklisting.
Blocklist status
Whether your IP is listed on a Microsoft internal blacklist (blocklist).
Emails may be rejected outright or routed to junk folders. Remediation is necessary.
IP reputation
Overall health score based on sending behavior to Outlook.com users.
Directly influences inbox placement rates and overall deliverability.
Proactive monitoring and swift action based on SNDS insights are key. Regular review of this data will help you identify potential issues before they escalate into major deliverability problems and ensure your email program remains effective.
While SNDS provides critical data, it's just one piece of the puzzle for overall email deliverability. To ensure consistent inbox placement, it's vital to implement and monitor other email authentication protocols like SPF, DKIM, and DMARC. These records help mail providers verify that your emails are legitimate and prevent spoofing and phishing attempts.
Maintain rigorous list hygiene by regularly cleaning your subscriber lists to remove inactive or invalid email addresses. Segment your audience to send targeted, relevant content, which can improve engagement and reduce complaint rates. Finally, consistently warm up any new IPs or domains to build a positive sending history gradually. These practices, combined with SNDS insights, will collectively boost your deliverability.
Views from the trenches
Best practices
Always initiate communication with your ESP's support team when attempting to gain SNDS access for your dedicated IPs.
Request regular SNDS reports from your ESP if direct portal access is not feasible due to their policies.
Understand that authorization emails are tied to PTR records, which are managed by the IP owner, typically the ESP.
Common pitfalls
Attempting to change the Microsoft SNDS authorization email address without contacting your ESP first.
Expecting direct SNDS portal access from your ESP without understanding their control and privacy concerns.
Ignoring SNDS data, leading to undetected deliverability issues and potential blocklisting (blacklisting).
Expert tips
If an ESP manages your IPs, they are the 'network owner' for SNDS purposes, and their approval is required.
Be aware that some ESPs may cite difficulties in revoking client access as a reason for not granting direct SNDS portal access.
Even if direct access is granted, the SNDS interface can be clunky, so ongoing communication with your ESP remains important.
Marketer view
Initially, I struggled with the SNDS authorization process for my IPs, as it presented an unfamiliar email address for verification. This issue was resolved by understanding the underlying IP ownership structure.
2019-05-07 - Email Geeks
Expert view
The authorization email addresses in SNDS are directly tied to the PTR records of the sending IPs, meaning ESPs typically control access. If you're using an ESP, requesting access directly from them is the correct approach.
2019-05-07 - Email Geeks
Key takeaways for ESP users
Accessing Microsoft SNDS data when using an Email Service Provider is not always straightforward due to IP ownership and authorization complexities. While direct portal access may be limited, working collaboratively with your ESP to obtain regular SNDS reports is often the most effective solution.
This approach ensures you have the necessary insights to monitor your sending reputation, identify issues like blocklistings or high complaint rates, and take corrective action to optimize your email deliverability to Microsoft mailboxes.
does not provide an easy way for an ESP to revoke access once it's granted to a specific user, especially if that dedicated IP is later reassigned. This raises privacy and security concerns for the ESP, as historical sending data could remain accessible to a former user of that IP.
Outlook.com users.
