Why does Microsoft scan links in emails?

Microsoft scans links in emails primarily for security purposes. Features like Safe Links and SmartScreen in Microsoft Defender for Office 365 automatically check URLs for phishing, malware, and other malicious content to protect users at the time of click. This proactive scanning helps prevent users from accessing dangerous websites.

How can I differentiate between real clicks and scanner clicks?

It can be challenging to differentiate between real clicks and scanner clicks. Automated scanner clicks often occur very rapidly after an email is sent, sometimes within seconds, and originate from Microsoft's IP ranges. Real user clicks typically show more varied timing and geographic distribution. Analyzing your email logs for specific patterns can help in this differentiation.

Can I stop Microsoft from scanning my email links?

No, you cannot directly stop Microsoft from scanning links in emails destined for their users. This is a core security feature of their platform. However, maintaining a strong sender reputation, ensuring proper email authentication (SPF, DKIM, DMARC), and providing clean, legitimate content can positively influence how Microsoft perceives and processes your emails. If scanning becomes problematic, you can engage with Microsoft's Postmaster support to seek assistance.

How does Microsoft's link scanning affect my email deliverability?

Microsoft's link scanning generally doesn't negatively impact your email deliverability if your emails are legitimate and have a good sender reputation. However, the inflated click metrics can lead to misinterpretations of campaign performance. In rare cases, if your links are mistakenly flagged as malicious, it could lead to deliverability issues, but this is usually due to underlying reputation problems rather than the scanning itself. You can find more information about email deliverability issues in our guide.

What should I do if my domain appears on a blacklist due to excessive scanning?

If your domain is unexpectedly added to a blocklist (or blacklist) due to perceived issues from scanning, it's crucial to identify the cause. This could be due to a genuine security concern, or it might be a false positive. You should: 1. Confirm the blacklist listing . 2. Review your email content and sending practices. 3. Contact the blacklist operator or Microsoft support with evidence of legitimate sending. 4. Work on improving your overall sender reputation.

Why is Microsoft scanning links in my emails at a high rate? - Sender reputation - Email deliverability - Knowledge base

Recently, I've observed a significant increase in requests hitting our application from Microsoft-controlled IP addresses. These aren't user clicks, but rather automated scans originating from Microsoft's email security features, often at rates that seem disproportionate to our actual email sending volumes. It raises questions about why this high rate of scanning occurs and what impact it has on our email programs.

This phenomenon is primarily driven by Microsoft 365's 'Safe Links' and 'SmartScreen' features. These advanced threat protection mechanisms are designed to safeguard users from malicious URLs embedded in emails. While their intent is to enhance security, the sheer volume of these automated clicks and scans can lead to unexpected challenges for email senders.

The core issue for many senders is the discrepancy between reported click-through rates and actual user engagement. These scanner clicks often inflate metrics, making it difficult to accurately assess campaign performance and user interest. Understanding the underlying reasons for this high scanning rate and its implications is crucial for effective email deliverability and analytics.

The purpose of Microsoft's advanced threat protection

Microsoft's primary objective with features like Safe Links, part of Microsoft Defender for Office 365, is to protect its users from phishing attacks, malware, and other malicious content. In today's threat landscape, email remains a primary vector for cyber threats, making robust link scanning an essential security layer for any major inbox provider.

Safe Links provides time-of-click protection. When an email with a link arrives, Microsoft's systems actively scan the URL to check its reputation and content. If the link is deemed suspicious, it may be rewritten to redirect through a Microsoft safety page, blocking access to potentially harmful sites. This scanning isn't just a one-time event upon arrival; it can also occur when a user hovers over a link, or even after the email has been delivered to the inbox.

This advanced security feature is a core component of Microsoft's strategy to safeguard its vast user base, encompassing both consumer Outlook.com accounts and corporate Microsoft 365 environments. It's an automated, systemic process that is integral to their security posture, rather than a setting that senders can directly influence or disable.

Impact on email analytics and sender metrics

One of the most significant impacts of Microsoft's high link scanning rate is the inflation of email metrics, particularly open and click rates. Automated scanners will 'click' every link within an email, including tracking pixels, which can artificially boost your reported engagement figures. This makes it challenging to gauge the true effectiveness of your campaigns and understand genuine subscriber interest.

The inflated metrics can lead to misinformed decisions about content, subject lines, and audience segmentation. Furthermore, in some cases, these scanner clicks can inadvertently trigger actions intended for users, such as one-click unsubscribes, even when the recipient did not intend to opt out. This adds a layer of complexity to managing your subscriber lists.

Understanding how to differentiate between legitimate user engagement and scanner activity is vital. Relying solely on raw click data can paint an inaccurate picture of your email program's health and lead to incorrect assumptions about your sender reputation (or lack thereof). Automated clicks are a significant factor to consider.

Metric	Traditional interpretation	With Microsoft Safe Links
Total clicks	Direct indicator of user engagement with links.	Inflated by automated scans; does not solely reflect user action.
Unique clicks	Number of distinct users who clicked a link.	Still impacted by scanners; may show clicks from bots before users.
Click-through rate (CTR)	Percentage of delivered emails that received a click.	Often appears higher than actual user engagement due to scans.

Strategies for managing high scanning volumes

While there's no magic switch to turn off Microsoft's security scanning, you can implement strategies to manage its impact. The key is to focus on factors within your control, such as maintaining a strong sender reputation and ensuring your email practices align with industry best practices.

If you're experiencing excessively high scanning rates, especially if it seems out of proportion to your sending volume or if it's impacting your service, consider opening a support ticket with Microsoft through their Outlook.com Postmaster support portal. Be prepared to provide detailed logs and context. Persistence is often necessary, as initial responses might direct you to general support tiers. Clearly explain the issue and request escalation if needed.

It's also beneficial to analyze if certain campaigns, content types, or recipient segments are triggering higher scan rates. For instance, emails with many links, or those sent to corporate domains with stricter filtering, might see more intense scrutiny. Proactive reputation management is your best defense against unintended consequences of security scanning, helping to prevent your domains from landing on any email blacklist (or blocklist).

Long-term solutions

Authentication standards: Ensure your emails consistently pass SPF, DKIM, and DMARC checks. Strong authentication builds trust and can reduce the perceived risk of your emails, potentially leading to less aggressive scanning over time. For more information, read our practical guide to understanding domain reputation.
List hygiene: Regularly clean your email lists to remove inactive or invalid addresses, reducing bounces and spam trap hits. A clean list signals good sending practices.
Content quality: Avoid suspicious phrasing, excessive links, or common phishing indicators in your email content that might trigger heightened scrutiny from scanners.

Immediate steps

Log analysis: Dive into your server logs to identify the specific IP ranges and user agents associated with the high scan rates. This data is critical for any communication with Microsoft support.
Microsoft support engagement: Submit detailed tickets to Microsoft's postmaster team, providing evidence of excessive scanning and its impact on your operations. Clearly outline your legitimate sending practices. You can learn more about how to prevent Outlook from flagging email links here.
Monitoring and adjustment: Continuously monitor your deliverability and adjust your sending strategy based on feedback from Microsoft and your own analytics. This includes understanding why Microsoft Office 365 filters email.

Views from the trenches

Best practices

Consistently monitor your email logs for unusual spikes in clicks, especially from Microsoft-controlled IP ranges.

Implement strong email authentication (SPF, DKIM, DMARC) to build and maintain trust with inbox providers.

Engage with Microsoft's postmaster support channels for specific issues or questions about scanning behavior.

Common pitfalls

Misinterpreting inflated click-through rates as genuine user engagement, leading to skewed campaign performance analysis.

Neglecting to address underlying sender reputation issues that might trigger heightened scrutiny from security scanners.

Failing to differentiate between legitimate user clicks and automated security scans in your analytics.

Expert tips

Ensure your email content and links are consistently clean and free of anything that could be flagged as suspicious.

Regularly review your recipient engagement metrics, paying close attention to anomalies that might indicate bot activity.

Be prepared to provide detailed evidence and logs to Microsoft support when reporting excessive scanning.

Marketer view

Marketer from Email Geeks says that while some senders have managed to reduce Microsoft's scanning activity, the exact methods for achieving this are not widely known.

Jan 23, 2024 - Email Geeks

Marketer view

Marketer from Email Geeks says that the volume of robot requests might decrease as sender reputation with Microsoft improves, but it can also randomly spike. Corporate filter settings can also mean scanning may never fully go away. They advise opening a postmaster ticket with Microsoft, potentially requiring escalation.

Jan 23, 2024 - Email Geeks

Navigating the landscape of email security

Microsoft's high rate of link scanning is a fundamental aspect of its robust email security infrastructure, designed to protect users from evolving cyber threats. While it presents challenges for email senders in terms of accurate analytics and potential false positives, it's a mechanism that is here to stay.

For email senders, the key is not to fight against this system, but to understand it and adapt. This involves recognizing that raw click metrics from Microsoft domains may be skewed and developing alternative methods for gauging true user engagement. Consider tracking conversions, replies, or other post-click actions as more reliable indicators of campaign success.

Maintaining a pristine sender reputation through consistent authentication, good list hygiene, and high-quality content remains paramount. A strong reputation can influence how aggressively your links are scanned, although it may not eliminate the behavior entirely. It's about building trust with Microsoft and other inbox providers over time, ensuring your emails are perceived as legitimate and safe.

Continuous monitoring of your email program and proactive engagement with Microsoft's postmaster support when anomalies arise are essential practices. By taking a strategic and informed approach, you can navigate the complexities of Microsoft's link scanning and ensure your email deliverability remains high, even in an increasingly secure email environment.