How to identify all Microsoft domains contributing to IP blocks in SNDS?

Identifying all these contributing Microsoft domains requires a more sophisticated approach than simple keyword matching. It involves understanding how SNDS data relates to your sending patterns, even when you're not intentionally targeting Microsoft inboxes. Unexpected activity, such as significant DATA commands for a supposedly idle IP, can be a clear indicator that some Microsoft-affiliated domains are still receiving mail.

Key findings

• SNDS timezone: Microsoft SNDS data is reported in GMT, which requires time-zone adjustments for accurate analysis of activity spikes or block events.
• Limited SNDS scope: SNDS primarily tracks issues with Microsoft's consumer domains (e.g., Hotmail, Outlook.com) and generally does not include data for Office 365 (O365) business accounts. For more on this, see Does Microsoft SNDS monitor Office 365?.
• Hidden domains: A significant number of domains beyond the common four (hotmail, outlook, msn, live) are associated with Microsoft, including country-specific variations (e.g., hotmail.co.uk) and domains that use Microsoft's MX servers for their email hosting. These can be a source of unexpected blocklistings.
• MX record importance: Looking up domains by their MX records is a critical step to uncover all Microsoft-affiliated email destinations that might be contributing to IP blocks in SNDS.
• Unexpected activity: The presence of DATA commands in SNDS for an IP that is supposedly not sending to Microsoft suggests that some form of email traffic is still occurring, possibly due to uncleaned lists or automated systems. This often leads to a blocklist or blacklist entry.

Key considerations

• Expand domain suppression: Implement a more comprehensive suppression strategy that accounts for all domains routing through Microsoft's MX records, not just the primary consumer domains. This is key to resolving email blocking issues.
• Verify all sending sources: Conduct a thorough audit of all automated systems and API-based email senders to ensure no unintended mail is being directed to Microsoft-affiliated domains from the affected IP. Learn more about what Microsoft SNDS is.
• Leverage deliverability dashboards: Utilize robust deliverability dashboards or tools that allow filtering by MX records to identify the full list of domains receiving email and using Microsoft's infrastructure.
• Regular data analysis: Consistently analyze SNDS data, paying attention to even low volumes of unexpected activity, as these can signal underlying issues contributing to a blocklist entry.
• Review list hygiene: Ensure your email lists are clean and free of stale or problematic addresses that might be triggering spam traps or complaints, even if sending volume appears low.

The insights from marketers highlight the challenge of comprehensively identifying all Microsoft-affiliated email destinations and the need for more granular data to troubleshoot these elusive IP blocks.

Key opinions

• Puzzling blocks: Marketers are often puzzled by an IP being blocked in SNDS, seeing hundreds of DATA commands daily, even when they believe they aren't actively sending to Microsoft domains from that IP.
• Narrow domain focus: Many marketers initially restrict their suppression efforts to the four main Microsoft domains (Hotmail, Outlook, MSN, Live), assuming these cover the full spectrum of Microsoft-hosted inboxes, which is often not the case. For a more comprehensive list, consider what Microsoft domains to exclude.
• Unaccounted traffic: The persistent observation of DATA commands suggests that some form of email traffic is still reaching Microsoft domains, even if primary campaigns are suppressed, indicating overlooked sending sources or recipient addresses.

Key considerations

• Comprehensive domain mapping: Marketers should invest in tools or processes to map all domains that resolve to Microsoft's MX records, including country-specific variations and custom domains hosted on Microsoft's infrastructure. This can help understand Microsoft SNDS.
• Automated system review: It's vital to check all automated or API-based email systems that might be inadvertently sending email to Microsoft-affiliated domains, potentially causing blocklists or a sudden drop in sender reputation.
• Granular data analysis: Utilize advanced deliverability dashboards to filter and analyze email sending data by MX record, providing visibility into the exact domains causing issues.

Their insights underscore the need for sophisticated data analysis and proactive measures to manage sender reputation effectively with Microsoft.

Key opinions

• MX record is key: Experts stress that looking up domains by their MX records is the most accurate way to identify all Microsoft-affiliated email destinations, including country-specific variations (like hotmail.co.uk) and domains (e.g., webtv) that route through Microsoft's servers, even if they aren't explicit Microsoft brands.
• Extensive domain ecosystem: There are far more domains routing through Microsoft's MX than commonly assumed, with one expert noting over 90 distinct domains in their data that point to Outlook MX servers.
• SNDS and O365 distinction: SNDS data typically does not cover Office 365 (O365) environments, meaning issues with business email accounts hosted by Microsoft won't be reflected in SNDS. This is an important consideration for troubleshooting Microsoft deliverability issues.
• Hidden sending: Unexpected activity in SNDS for a supposedly quiet IP suggests reviewing all API-based or automated sending systems that might be inadvertently sending email, as even low volumes can trigger a blocklist.

Key considerations

• Dynamic domain identification: Relying on static lists of Microsoft domains is insufficient; senders need a dynamic approach, potentially using scripts or tools, to continuously identify domains pointing to Microsoft's MX records.
• Account for all traffic: Ensure that every email sending channel is accounted for and configured to prevent unintentional sending to Microsoft domains from sensitive IPs. This is particularly relevant when attempting to detect and resolve Microsoft IP blocks.
• Integrated data analysis: Combine SNDS data with internal logs and bounce data to get a complete picture of email deliverability, especially for domains outside of typical consumer mailboxes. This is key to solving Microsoft deliverability issues.

While informative, the documentation implicitly highlights that SNDS focuses on specific consumer domains and offers a particular view of deliverability, rather than a comprehensive overview of all Microsoft email traffic.

Key findings

• Core purpose: Microsoft SNDS is designed to provide senders with critical data on their IP addresses to help resolve email delivery issues when sending to Outlook.com, Hotmail.com, Live.com, and MSN.com.
• Available metrics: SNDS provides metrics such as complaint rates, spam trap hits, and SMTP activity (e.g., DATA commands), offering insights into an IP's sending behavior and reputation.
• Block indication: The platform can explicitly indicate if an IP address is blocked and may provide additional context, such as a block due to abuse complaints.
• GMT standard: All data presented within the SNDS interface is in Greenwich Mean Time (GMT), requiring senders to consider this when analyzing timestamps.

Key considerations

• Targeted scope: Documentation implies that SNDS's primary focus is on Microsoft's consumer domains, suggesting that a comprehensive deliverability strategy might need to look beyond SNDS for issues with other Microsoft-hosted or business domains. This is important for understanding SNDS data reliability.
• Proactive monitoring: Regularly checking SNDS is crucial for identifying early warning signs of reputation degradation, such as rising complaint rates or unexpected increases in DATA command counts for a given IP.
• Actionable insights: The details provided within SNDS, particularly regarding block reasons, should be used to guide specific remediation efforts to prevent or resolve blocklists and blacklists.
• Integrated strategy: While SNDS is a valuable tool, it should be part of a broader email deliverability strategy that includes monitoring other metrics and potential sources of email traffic. This helps gain deeper insights into SNDS.