How to Configure Junk Mail Filter Settings in Outlook 365: A Concise Guide

Last Updated on May 28, 2023 by Amit Bansal

Managing your email inbox can be a daunting task, especially when it comes to filtering out unwanted spam or junk messages.

With Outlook 365, we have the ability to configure the Junk Mail Filter settings to ensure a clutter-free inbox while reducing the risk of legitimate emails ending up in the junk folder.

To get started, navigation through the Junk Mail Filter settings requires understanding the various protection levels and customization options available in Outlook 365.

By tailoring these settings to our specific needs, we can strike a balance between blocking unwanted emails and allowing important messages to reach our inboxes without any hassle.

Remember, a clean and organized inbox can save us time and effort while improving our overall email experience.

Understanding Junk Mail Filter in Outlook 365

Importance of Junk Email Filtering

Junk email filtering is a crucial feature in Outlook 365, as it helps protect us from unwanted spam and potentially harmful emails.

By automatically filtering and moving potential junk emails to the Junk Email folder, Outlook reduces the clutter in our inboxes and significantly lowers the risk of accidentally opening malicious emails.

However, it’s important to note that the level of protection in the Junk Email Filter can be adjusted according to our preferences.

Microsoft 365 Defender and Exchange Online Protection

Microsoft 365 Defender and Exchange Online Protection (EOP) work together to provide a comprehensive layer of security for our Outlook email inboxes.

EOP offers anti-spam policies that can be configured to filter out junk emails based on different criteria.

Some of the key features of EOP include:

  • Policy filtering: Analyzes emails according to established policies and takes appropriate actions.
  • Content filtering: Scans the content of emails to identify and filter out junk emails.
  • Microsoft Defender for Office 365: Provides additional protection against malicious links and attachments, as well as phishing attempts.

To configure junk email settings on Exchange Online mailboxes, we can follow the guidelines provided in Microsoft’s documentation.

By customizing these settings, we can improve the efficiency and accuracy of Outlook 365’s junk email filtering system.

In conclusion, understanding and configuring the Junk Mail Filter in Outlook 365 is essential to provide a secure and clutter-free email experience.

By leveraging the features offered by Microsoft 365 Defender and Exchange Online Protection, we can create a tailored email filtering system that meets our specific needs.

Configuring the Junk Email Filter Settings

Safe Senders List

To ensure that important emails do not end up in the junk folder, Outlook 365 allows us to create a Safe Senders list.

To do this, open Outlook and navigate to Settings >> Mail >> Accounts >> Block or Allow.

Under the Safe Senders section, add email addresses or domains that you trust.

Emails from these senders or domains will bypass the junk email filter and go directly to your inbox.

To remove an email address or domain from the list, simply click on it and select Remove.

Blocked Senders List

Similarly, we can create a Blocked Senders list to prevent unwanted emails from reaching our inboxes.

In the same settings area (Settings > Mail > Accounts > Block or Allow), find the Blocked Senders section.

Here, we can add email addresses or domains that we don’t trust.

Emails from these senders or domains will be automatically sent to the junk email folder.

To unblock a sender, click on the email address or domain and select Remove.

Safe Recipients List

Outlook 365 also allows us to designate specific email addresses or mailing lists as Safe Recipients.

By adding these to the Safe Recipients list, we can ensure that emails sent to these addresses or groups will not be accidentally marked as junk.

To create a Safe Recipients list, navigate to Settings > Mail > Accounts > Block or Allow and locate the Safe Recipients section.

Add email addresses or mailing list names and click Save to update the list.

Automatic Filtering

By default, Outlook 365’s junk email filter is set to “Low” which catches only the most obvious spam. However, we can adjust the filter’s aggressiveness to better suit our needs.

To do this, go to Settings > Mail > Accounts > Block or Allow and find the Junk email filter section.

Here, we can choose from a few options:

  • No automatic filtering: The junk email filter is completely disabled.
  • Low: Catches only the most obvious spam.
  • High: Catches more spam but may occasionally classify legitimate emails as junk.
  • Exclusive: Only emails from senders in our Safe Senders list will be delivered to the inbox, while all others are sent to the junk folder.

Choose the desired filtering level and click Save to apply the changes.

By configuring our Outlook 365 Junk Email Filter settings according to our preferences, we can effectively manage our email inbox while ensuring that important messages are not accidentally marked as junk.

Managing False Positives and Blocked Domains

In this section, we’ll discuss how to manage false positives and blocked domains in Outlook 365’s Junk Mail Filter settings.

We’ll cover whitelisting and blacklisting email addresses and domains, as well as adjusting the Spam Confidence Level to optimize email filtering.

Whitelisting Email Addresses and Domains

To minimize false positives, we can whitelist certain email addresses and domains in Outlook 365. Whitelisting allows us to specify trusted senders and their domains, effectively bypassing the spam filters for these contacts. To whitelist an email address or domain, follow these steps:

  1. Open Outlook 365 and navigate to Settings > Mail.
  2. Under Options, select Block or Allow.
  3. Under the Safe Senders section, add the desired email addresses or domains, and click Add. We can also remove previously added addresses or domains from the list if needed.

Blacklisting Email Addresses and Domains

Conversely, we may want to block specific email addresses or domains to prevent unwanted emails from reaching our inboxes.

To do this, we’ll blacklist these addresses and domains by following these steps:

  1. Open Outlook 365 and navigate to Settings > Mail.
  2. Under Options, select Block or Allow.
  3. Under the Blocked Senders section, add the email addresses or domains that we want to block, and click Add. As with whitelisting, we can remove entries from the list, if needed.

Spam Confidence Level

Outlook 365 uses the Spam Confidence Level (SCL) to determine the likelihood that an email is spam based on its content and other factors.

We can adjust the SCL to fine-tune spam filtering for our needs. In general, a lower SCL will result in fewer false positives, whereas a higher SCL may filter out more legitimate emails, but increases the risk of false positives.

To configure the SCL in Outlook 365:

  1. Open Outlook 365 and navigate to Settings > Mail.
  2. Under Options, select Spam Filter.
  3. Adjust the SCL value according to our desired spam filtering sensitivity.

By carefully managing false positives, blocked domains, malware protection, and optimizing the SCL, we can effectively control the filtering of our incoming emails in Outlook 365.

This helps to ensure that legitimate emails reach our inboxes, while unwanted spam and potential malware are kept at bay.

Advanced Anti-Spam Configurations

Custom Anti-Spam Policies

As security administrators, we can create custom anti-spam policies in Office 365 to enhance the default protection level.

Custom policies can be tailored to the needs of our organization, ensuring targeted and effective protection against spam.

To configure a new custom policy, navigate to the Anti-spam policies page and select “Create” followed by “Inbound” from the drop-down list.

Provide a unique name and an optional description for the policy.

Mail Flow Rules

We can also set up mail flow rules in Office 365 to further refine our organization’s junk email filtering.

These rules allow us to define specific conditions and actions related to spam management, ranging from simply marking a message as spam to completely blocking it.

To create a mail flow rule, go to the organization management settings and navigate to the mail flow section.

Some examples of mail flow rules we can create are:

  • Increase the spam score of messages containing specific keywords
  • Block messages from specific senders or domains
  • Route spam messages to a specific folder or mailbox

Phishing Messages

Phishing messages are a common threat in email communication, and we need to configure Outlook 365 to effectively handle them.

Outlook’s Junk Email Filter has built-in settings for dealing with phishing messages, and they can be adjusted to suit our organization’s needs.

To change the level of protection against phishing messages, open the Junk Email Options and choose the desired level of protection:

  • No Automatic Filtering: Turns off the automatic Junk Email Filter.
  • Low: Filters obvious junk messages.
  • High: Filters most junk messages; might classify some legitimate messages as junk.

Threat Policies

To further enhance our organization’s security, we can configure threat policies in Office 365.

These policies allow us to define settings for dealing with malware, phishing, and other email threats.

The Defender for Office 365 checks can be customized for more effective filtering.

Some examples of threat policies we can configure are:

  • Customizing settings for attachments and linked content in messages
  • Configuring Advanced Threat Protection (ATP) policies
  • Setting up anti-phishing protection for specific domains

In summary, configuring advanced anti-spam settings in Office 365 involves setting up custom anti-spam policies, and mail flow rules, adjusting protection against phishing messages, and defining threat policies.

By taking these measures, we can create a more secure email environment for our organization.

Using Outlook on the Web and

Blocking and Unblocking Senders

Managing your junk mail settings in Outlook on the Web and is easy.

To block a particular sender, open the email and click on the three dots at the top of the message. Then, select Block Sender.

From now on, any email from that sender will be automatically moved to our junk email folder.

In case we want to unblock a sender that we accidentally blocked, navigate to Settings > Mail > Junk email.

Under Blocked senders and domains, find the sender’s email address or domain, and click on the trash icon to remove it from the list.

By doing this, their emails will no longer be treated as spam.

Managing Clutter and Spam Email and Outlook on the Web use a smart feature called Clutter to manage and sort our low-priority messages.

Clutter analyzes our email habits and determines which messages are less important.

It then moves those messages to the “Clutter” folder automatically. This helps us focus on essential emails in our inboxes.

We can also set specific rules for classifying emails as spam. Navigate to Settings > Mail > Junk email. Here, we can:

  • Safe senders and domains: Add email addresses and domains we trust to never treat their messages as spam.
  • Blocked senders and domains: Add email addresses and domains that should always be considered spam.
  • Safe mailing lists: Add email addresses of mailing lists we trust to never treat their messages as spam.
  • Blocked senders: Manage the email addresses we have previously blocked.

In addition to the above configurations, we can also use the Delete All option to easily remove all spam emails in the junk folder.

Simply navigate to the Junk Email folder, click on the Delete All button, and confirm our action.

This will quickly and permanently delete all of the messages currently in our junk folder.

By properly managing our Clutter and junk email settings in Outlook on the Web and, we can ensure a more organized inbox, free of unwanted spam and clutter.

Inbound and Outbound Mail Protection

Outlook 365 offers comprehensive inbound and outbound mail protection to maintain the security and deliverability of your emails.

As part of its mail filtering capabilities, it utilizes Exchange Online Protection to ensure that your communications are secure and free from spam or malware.

Role of Exchange Online Protection

Exchange Online Protection (EOP) plays a crucial role in securing both inbound and outbound mail.

We rely on EOP to scan incoming mail for threats such as spam, malware, and phishing attempts. EOP effectively filters inbound mail by:

  • Content filtering: Detecting and quarantining suspicious messages based on their content and sender reputation.
  • Attachment and URL scanning: Identifying potentially harmful attachments or links embedded in emails.
  • Message limiting: Limiting the number of messages sent from a single mailbox within a specific period to prevent spam outbreaks.

For outbound mails, EOP performs checks on your messages to ensure they adhere to security and compliance policies before they’re sent to recipients. These checks include:

  • Spam and malware scanning: Scan email content and attachments for any spam or malware signature.
  • Domain and sender verification: Validating the sender’s domain and identity to maintain email authentication and deliverability.
  • Outbound rate limiting: Imposing sending limits on messages to prevent your domain from being flagged as a spam sender.

By using Exchange Online Protection in conjunction with Outlook 365, we are able to ensure that our inbound and outbound mail is protected from potential threats and complies with industry best practices.

This not only helps us maintain the integrity of our email communications but also enhances the overall email experience for our users.

Configure junk email settings on Exchange Online mailboxes

Configure outbound spam policies


We have discussed the importance of configuring Junk Mail Filter settings in Outlook 365 to ensure a clean and safe inbox.

By taking the necessary steps to adjust these settings, we can reduce the amount of spam and unwanted messages cluttering our inboxes.

Outlook 365 offers various options to manage junk mail, such as changing the level of protection in the Junk Email Filter and configuring junk email settings on Exchange Online mailboxes.

Furthermore, users can edit spam filtering settings to make them more aggressive and move more emails into the spam folder.

We recommend spending time exploring these features and adjusting them according to your specific needs.

By doing so, we can create a more organized email environment, allowing us to focus on important messages and work more efficiently.

In addition, we should always remain vigilant when dealing with suspicious emails, as the filters may not catch every potential threat.

By combining Outlook 365’s powerful filtering tools with our own cautious email practices, we can maintain a secure and clutter-free Inbox.

Frequently Asked Questions

We often receive questions regarding the configuration of Junk Mail Filter settings in Outlook 365.

In this section, we will address some of the most frequently asked questions to provide helpful information on this topic.

One common question is about adjusting the level of protection in the Junk Email Filter.

You can change the protection level in Outlook by clicking Home > Delete group > Junk > Junk E-mail Options.

From there, you can choose the desired level of protection, ranging from “No Automatic Filtering” to “High” protection levels.

Be aware that setting a higher protection level increases the risk of legitimate emails being marked as junk and moved to the Junk Email folder.

For more information, refer to this Microsoft Support article.

Another frequent inquiry involves configuring spam filter policies.

You can set up these policies in Office 365 by navigating to the Anti-spam policies page and selecting “Create Create policy” and then choosing “Inbound” from the dropdown list.

This will initiate the new anti-spam policy wizard where you can input a unique name and an optional description for the policy. For a detailed guide on configuring spam filter policies, refer to this Microsoft Learn article.

Users also often ask about editing Outlook’s spam filtering settings to make them more aggressive. By default, Outlook is set to “No automatic filtering.

To increase the aggressiveness of the filtering, you can change the settings in the Junk Email Options dialogue.

There are three additional levels of filtering you can choose from, such as “Low,” “High,” or “Safe Lists Only.” For more tips on spam filtering in Outlook, check out this Microsoft 365 page.

We hope that this information helps you better understand how to configure Junk Mail Filter settings in Outlook 365.

Always be cautious and deliberate about adjusting your settings to ensure that important emails are not mistakenly marked as junk or spam.

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Amit Bansal

Hello, my name is Amit Kumar Bansal, and I am the founder of Through this blog, I focus on Microsoft Outlook, offering insightful and informative content. Additionally, I produce educational videos on YouTube to further enhance the understanding of my audience. visit my YouTube Channel

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