Summary
Microsoft Smart Network Data Services (SNDS) primarily monitors the reputation of IP addresses sending to Microsoft's consumer mail services, such as Outlook.com and Hotmail. It provides insights into how Microsoft views the sending reputation of IPs, helping senders understand and improve their deliverability to these specific domains. However, a common point of confusion arises regarding its coverage of domains hosted by Office 365. While Office 365 infrastructure often uses Microsoft's shared IP space, SNDS access and data are traditionally tied to the IP address, not explicitly to individual custom domains hosted within Office 365. This distinction is crucial for organizations managing their email deliverability.
Key findings
- Primary focus: SNDS offers reputation data for IP addresses sending to Microsoft's consumer domains, including outlook.com, Hotmail, and Live accounts.
- Office 365 distinction: SNDS does not directly monitor the reputation of individual custom domains hosted on Office 365. Instead, it tracks the reputation of the underlying sending IP addresses that handle mail for those domains.
- IP-centric data: The data provided by SNDS is primarily focused on IP address reputation, including factors like complaint rates, spam trap hits, and blocklist (or blacklist) status.
- Deliverability insights: Even for Office 365 users, understanding the reputation of the IPs used by their Email Service Provider (ESP) or Microsoft's shared IPs is vital for deliverability to Microsoft environments. This is particularly relevant if emails are going to spam or are being throttled. For more details, see our guide on Microsoft throttling issues.
Key considerations
- Shared vs. dedicated IPs: Organizations using shared IP pools (common with many ESPs and even Office 365 for outbound mail) must monitor the collective reputation of these IPs. SNDS can provide valuable insight into these shared IPs.
- Access for ESP users: If you send through an ESP, you may need to coordinate with them to gain access to the relevant SNDS data for the IPs they use on your behalf. Our article on getting SNDS access when using an ESP has more information.
- Complementary tools: While SNDS is IP-focused, monitoring your domain reputation through other means, such as DMARC reports, is crucial for overall deliverability (particularly for domain-based reputation at other mailbox providers).
- Documentation clarity: The distinction between Outlook.com and Office 365 environments is often implicit in Microsoft's documentation, leading to confusion for senders trying to understand their reputation for hosted domains.
What email marketers say
Email marketers often find the scope of Microsoft SNDS confusing, especially when it comes to differentiating between reputation monitoring for consumer-facing Microsoft services (like Outlook.com) and business-oriented Office 365 hosted domains. Many marketers, particularly those whose clients use ESPs and do not own their sending IP addresses, express a desire for clearer guidance on how their email deliverability is assessed for Office 365 destinations through SNDS. The general consensus among marketers is that SNDS is indeed valuable, but its specific application to Office 365 hosted domains can be unclear, prompting questions about IP versus domain reputation monitoring.
Key opinions
- Common confusion: Many marketers are unsure whether SNDS provides reputation data specifically for domains hosted by Office 365, similar to how Google Postmaster Tools works for G Suite domains.
- IP vs. domain: The primary understanding is that SNDS focuses on the IP addresses sending to Outlook.com, Hotmail, and similar consumer services, rather than specific custom domains hosted on O365, even if those domains use Microsoft's MX records.
- Documentation gap: Marketers frequently note a lack of explicit documentation from Microsoft clarifying the relationship between SNDS and Office 365 hosted domains, leading to reliance on community discussions for clarification.
- ESPs and IP ownership: For marketers whose clients use ESPs and do not own their sending IPs, accessing relevant SNDS data for those IPs is a key concern for understanding their deliverability to Microsoft endpoints. We discuss IP reputation in business partnerships in detail.
Key considerations
- Practical application: Marketers should focus on the IP addresses their emails traverse to reach Microsoft inboxes, regardless of whether the recipient domain is a consumer Outlook.com account or an Office 365 hosted domain.
- Email flow awareness: Understanding that mail for custom domains hosted on Office 365 still passes through Microsoft's protection infrastructure (e.g., mail.protection.outlook.com) reinforces why IP reputation monitored by SNDS remains relevant.
- Reputation tools: Even if SNDS isn't domain-specific for O365, it remains a critical tool for assessing overall sending health to Microsoft properties. Supplementing this with DMARC reports can provide more granular insights into domain-level deliverability to Microsoft and beyond.
- Distinguishing services: It is important for marketers to recognize that Outlook.com and Office 365, while sharing underlying infrastructure, operate as distinct email solutions with different implications for reputation monitoring via SNDS.
Marketer view
Email marketer from Email Geeks indicates persistent confusion regarding SNDS and Office 365 hosted domains. They find it hard to understand if SNDS provides insights for custom domains using Office 365, much like Google Postmaster Tools does for G Suite domains. This gap in clarity often requires community verification.
Marketer view
Email marketer from Email Geeks confirms that SNDS is primarily for Outlook.com hosted domains. This answer helped clarify their understanding, reinforcing that the tool's focus is on Microsoft's consumer email services, which often correlates with general deliverability to Microsoft-affiliated mailboxes.
What the experts say
Experts in email deliverability clarify that Microsoft SNDS operates primarily at the IP level, providing data on traffic sent to Microsoft's consumer properties such as Outlook.com and Hotmail. While Office 365 utilizes Microsoft's infrastructure, SNDS does not offer specific domain-level reputation metrics for custom domains hosted on Office 365. The consensus is that SNDS is a tool for understanding how Microsoft's filtering systems perceive the trustworthiness of an IP, which implicitly affects deliverability to all Microsoft-affiliated mailboxes, including those managed under Office 365 tenants.
Key opinions
- IP-centric monitoring: SNDS provides reputation feedback based on sending IP addresses, not individual customer domains hosted within Office 365.
- Consumer services focus: The primary data points in SNDS are for mail flowing to Microsoft's consumer-facing services like Outlook.com and Hotmail, which are distinct from the Office 365 business environment.
- Indirect relevance to O365: Although SNDS doesn't directly monitor O365 hosted domains, the reputation of IPs sending to Outlook.com can still impact overall deliverability to Office 365 recipients if the same sending IPs are used.
- Shared infrastructure: Experts acknowledge that Outlook.com and Office 365 share common underlying mail filtering codebases and IP space, meaning issues on one platform can influence the other.
Key considerations
- Holistic view: While SNDS provides IP reputation, a comprehensive view of deliverability to Microsoft environments requires looking at domain authentication (SPF, DKIM, DMARC) and complaint rates, which directly affect your overall domain reputation.
- Proactive monitoring: Regularly checking SNDS for any anomalies on your sending IPs is crucial, as early detection of blocklist or negative reputation can prevent widespread deliverability issues. This is especially true given that Outlook.com deliverability can be inconsistent.
- Impact of policy changes: Microsoft's new sender requirements, particularly regarding DMARC enforcement and explicit consent, will increasingly impact deliverability to Office 365 domains, even if SNDS doesn't report on them directly. Experts advise understanding how SNDS works in this evolving landscape.
- IP segmentation: For senders with high email volumes, segmenting traffic across different IPs can help isolate potential reputation issues, which can then be monitored more effectively through SNDS.
Expert view
Deliverability expert from SpamResource.com states that SNDS is a valuable tool for insight into Microsoft's reputation data, but stresses that it provides data at the IP level, not directly at the domain level for individual Office 365 hosted domains. This distinction is crucial for accurate interpretation of deliverability health.
Expert view
Deliverability expert from WordToTheWise.com explains that while Microsoft's consumer domains (Outlook.com, Hotmail) are closely monitored by SNDS, Office 365 custom domains inherit reputation from the sending IPs. If those IPs are shared with consumer traffic, their SNDS data can provide a proxy indicator of deliverability.
What the documentation says
Microsoft's own documentation on Smart Network Data Services (SNDS) primarily outlines its functionality as a tool for understanding the health and reputation of IP addresses sending mail to Microsoft consumer mail services. While Office 365 (M365) domains route through Microsoft's protection infrastructure, the SNDS portal focuses on the IP space associated with Outlook.com, Hotmail, and Live services. The documentation emphasizes the importance of sender reputation based on IP address history, complaint rates, and spam trap hits, providing data points crucial for deliverability to these specific endpoints, which implicitly impacts all mail processed by Microsoft.
Key findings
- IP-based reporting: SNDS provides data, such as IP status, complaint rates, and spam trap hits, tied directly to sending IP addresses. This is the core of its monitoring.
- Target audience: The documented scope of SNDS is specifically for traffic destined for Outlook.com, Hotmail, and Live services.
- No explicit O365 domain monitoring: Microsoft's public SNDS documentation does not explicitly state that it monitors the reputation of specific custom domains hosted by Office 365, focusing instead on the shared IP infrastructure that serves these domains.
- Mx records and SPF: Office 365 domains typically use MX records like *.mail.protection.outlook.com and SPF includes like spf.protection.outlook.com, indicating that all mail passes through the same protection mechanisms that SNDS monitors.
Key considerations
- Implicit coverage: Although not directly monitoring custom domains, the reputation of the underlying IPs reported in SNDS directly influences deliverability to Office 365 tenants, as they share the same inbound mail infrastructure.
- Sender registration: Senders need to register their IP addresses in SNDS to gain access to the data, regardless of whether they are sending to Outlook.com or Office 365 domains.
- Policy enforcement: Microsoft's email policies and filters apply broadly across its email ecosystem. A poor reputation reflected in SNDS for a specific IP will impact deliverability to all Microsoft domains it serves, including those hosted on Office 365. This aligns with their anti-spam protection overview.
Technical article
Microsoft documentation on SNDS outlines that the service is intended for legitimate email senders to monitor their IP health and reputation. It specifically addresses mail flow to Outlook.com, Hotmail, and Live services, implying that the data is focused on the consumer-facing mail platforms.
Technical article
The Microsoft SNDS portal details various metrics, including complaint rates, spam trap hits, and IP status (green, yellow, red), which are all tied to the IP address from which email originates. This confirms the IP-centric nature of the reputation monitoring provided by the service.
Related resources
9 resources
Related pages
Why am I not receiving Microsoft SNDS authorization emails or experiencing delays?
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