How to Ensure Your Emails Reach Your Recipients with Microsoft Hosted Exchange

Question:

How to prevent legitimate emails from being flagged as spam by Microsoft Hosted Exchange?

I work as an IT professional for a small municipality that uses Microsoft Hosted Exchange as our email service. Lately, we have noticed that many of our emails to external contacts, who are also using Microsoft services, are being marked as spam or rejected by their security filters. This is affecting our ability to communicate and do business with them.

We have followed all the best practices for email authentication, such as setting up DKIM, SPF, and DMARC records for our domain. We have also enforced a strict SPF policy to reject any unauthorized senders using our domain. According to the DMARC reports we receive, there are only a few attempts by spammers to spoof our domain, and they are all blocked by the major email providers.

We have contacted Microsoft support twice to find out why our emails are being flagged, but we have not received a satisfactory answer. We are wondering if there is anything else we can do to improve our email deliverability and avoid false positives. We would appreciate any advice or feedback from other experts who have faced similar issues or have successfully resolved them. Thank you.

Answer:

Email deliverability is a crucial factor for any business that relies on email communication with its customers, partners, or suppliers. However, sometimes legitimate emails may end up in the spam folder or get rejected by the recipient’s email service. This can cause frustration, confusion, and loss of trust among the parties involved.

One of the common reasons why legitimate emails are flagged as spam is because of the spam filtering policies of the email service provider. In this article, we will focus on Microsoft Hosted Exchange, which is a popular email service used by many organizations, including a small municipality that we work for as IT professionals.

We will share our experience of dealing with the issue of legitimate emails being marked as spam by Microsoft Hosted Exchange, and provide some tips and solutions that may help you avoid or resolve this problem in the future.

What is Microsoft Hosted Exchange and how does it filter spam?

Microsoft Hosted Exchange is a cloud-based email service that offers enterprise-grade features, such as security, reliability, compliance, and integration with other Microsoft products. Microsoft Hosted Exchange is part of the Microsoft 365 suite, which also includes other services such as SharePoint, OneDrive, Teams, and Office applications.

Microsoft Hosted Exchange uses a variety of techniques and tools to protect its users from spam, phishing, malware, and other email threats. Some of these tools are:

  • Microsoft Defender for Office 365: This is a comprehensive solution that provides advanced protection against email attacks, such as impersonation, spoofing, ransomware, and business email compromise. Microsoft Defender for Office 365 uses machine learning, artificial intelligence, and behavioral analysis to detect and block malicious emails, and also provides remediation and investigation capabilities for admins and users.
  • Spam Confidence Level (SCL): This is a rating system that assigns a score to each incoming email, based on the probability of it being spam. The score ranges from -1 (not spam) to 9 (certain spam). The SCL score determines how the email is processed by the spam filter. For example, emails with SCL 5 or higher are sent to the junk folder, while emails with SCL 6 or higher are quarantined by the admin.
  • Content Filter: This is a component of the spam filter that analyzes the content of each email, such as the subject, body, attachments, and links, and assigns an SCL score based on the presence of spam-like characteristics. The content filter uses several criteria, such as keywords, phrases, patterns, and heuristics, to identify spam.
  • Sender Reputation: This is a measure of the trustworthiness of the sender’s IP address, domain, and email address, based on the history of their email activity and feedback from recipients. The sender reputation affects the SCL score and the likelihood of the email being delivered or blocked. The sender reputation is updated dynamically, based on the sender’s behavior and reputation data from various sources, such as Microsoft’s own intelligence, third-party providers, and user reports.
  • What are the best practices for email authentication and why are they important?

    Email authentication is a process of verifying the identity and legitimacy of the sender of an email, and preventing unauthorized or malicious use of their domain or email address. Email authentication helps to protect the sender’s reputation, prevent spoofing and phishing attacks, and improve the deliverability and trustworthiness of their emails.

    There are three main standards for email authentication, which are widely adopted and supported by most email service providers, including Microsoft Hosted Exchange. These are:

  • DomainKeys Identified Mail (DKIM): This is a method of digitally signing an email with a cryptographic key that is associated with the sender’s domain. The recipient’s email service can verify the signature by looking up the public key in the sender’s DNS records. This way, the recipient can confirm that the email was sent by the authorized owner of the domain, and that it was not tampered with in transit.
  • Sender Policy Framework (SPF): This is a method of specifying which IP addresses are authorized to send emails on behalf of the sender’s domain. The sender publishes an SPF record in their DNS records, which lists the IP addresses or domains that are allowed to send emails for their domain. The recipient’s email service can check the SPF record and compare it with the IP address of the email’s source. This way, the recipient can reject any emails that come from unauthorized or spoofed sources.
  • Domain-based Message Authentication, Reporting, and Conformance (DMARC): This is a method of defining the policy and the actions that the recipient’s email service should take when receiving an email that fails the DKIM or SPF verification. The sender publishes a DMARC record in their DNS records, which specifies how the recipient should handle the email, such as accept, quarantine, or reject it, and also how to report the results of the verification to the sender. This way, the sender can monitor and control the delivery of their emails, and also receive feedback and statistics from the recipients.
  • These three standards work together to provide a comprehensive and robust email authentication system, which can significantly reduce the chances of legitimate emails being flagged as spam, and also protect the sender and the recipient from email fraud and abuse.

    What are the challenges and solutions for email deliverability with Microsoft Hosted Exchange?

    As IT professionals working for a small municipality that uses Microsoft Hosted Exchange as our email service, we have faced some challenges and issues with the email deliverability of our legitimate emails to external contacts, who are also using Microsoft services. We have noticed that many of our emails are being marked as spam or rejected by their security filters, which is affecting our ability to communicate and do business with them.

    We have followed all the best practices for email authentication, such as setting up DKIM, SPF, and DMARC records for our domain. We have also enforced a strict SPF policy to reject any unauthorized senders using our domain. According to the DMARC reports we receive, there are only a few attempts by spammers to spoof our domain, and they are all blocked by the major email providers.

    We have contacted Microsoft support twice to find out why our emails are being flagged, but we have not received a satisfactory answer. We are wondering if there is anything else we can do to improve our email deliverability and avoid false positives. We would appreciate any advice or feedback from other experts who have faced similar issues or have successfully resolved them.

    Based

on our research and experience, we have found some possible tips and solutions that may help us and others who are facing the same problem. These are:

  • – Check the content of your emails: One of the possible reasons why your emails are being flagged as spam is because of the content filter of Microsoft Hosted Exchange, which assigns an SCL score based on the presence of spam-like characteristics in your emails. Some of these characteristics may include:
  • – The use of spammy words or phrases, such as “free”, “guaranteed”, “urgent”, “click here”, etc.
  • – The use of excessive punctuation, capitalization, or formatting, such as “!!!”, “ALL CAPS”, “bold”, “red”, etc.
  • – The use of attachments or links that are suspicious, broken, or irrelevant, such as “.exe”, “.zip”, “.rar”, “bit.ly”, “tinyurl”, etc.
  • – The use of mismatched or misleading information, such as the subject, sender, reply-to, or from address, that does not match the content or the domain of the email.
  • To avoid triggering the content filter, you should review and revise the content of your emails, and make sure that they are clear, relevant, professional, and consistent. You should also avoid using any content that may be considered spammy, offensive, or inappropriate by the recipient.

  • – Check the reputation of your domain and IP address: Another possible reason why your emails are being flagged as spam is because of the sender reputation of your domain and IP address, which affects the SCL score and the likelihood of your emails being delivered or blocked. Your sender reputation is based on the history of your email activity and feedback from recipients, and it can be influenced by various factors, such as:
  • – The volume and frequency of your emails, which may indicate spamming or flooding behavior if too high or too low.
  • – The quality and relevance of your emails, which may affect the engagement and satisfaction of your recipients, and also the rate of complaints, bounces, unsubscribes, and spam reports.
  • – The security and hygiene of your email infrastructure, which may expose your domain or IP address to hacking, compromise, or abuse by spammers or malware.
  • To improve your sender reputation, you should monitor and optimize your email performance, and follow the best practices for email marketing and communication, such as:

  • – Segmenting and targeting your audience, and sending personalized and valuable emails that meet their needs and expectations.
  • – Maintaining a healthy and clean email list, and removing any invalid, inactive, or uninterested contacts.
  • – Testing and verifying your emails before sending, and ensuring that they are compatible and responsive across different devices and platforms.
  • – Following the email regulations and standards, such as the CAN-SPAM Act, the GDPR, and the email authentication protocols.
  • – Check the settings and preferences of your recipients: A third possible reason why your emails are being flagged as spam is because of the settings and preferences of your recipients, which may override or conflict with the spam filtering policies of Microsoft Hosted Exchange. Some of these settings and preferences may include:
  • – The junk email options of the recipient, which allow them to customize the level of protection, the safe and blocked send
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