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How to Block Top-Level Domain (TLD) in Microsoft 365?

Tightening online security has become a must-do job due to increasing cybercrimes. Deploy as many layers as possible if you are into online business. Today, we are going to talk about blocking TLD in Microsoft 365. It’s just one of many methods to enhance security. Blocking specific TLDs, such as .com, .org, or .net. in Microsoft 365 – can help prevent spam & phishing attacks. This guide will provide a step-by-step approach to how to block TLDs in Microsoft 365. TLD is short for Top-Level Domains.

Why Block Top-Level Domains?

You must be wondering why block TLDs, no? Well, here’s the answer: blocking TLDs can significantly reduce the number of unwanted emails – reducing the risk of cyberattacks. Certain TLDs are notorious for being used by malicious actors to send harmful content. You can reduce the risk of security breaches and protect sensitive information if you identify and block these TLDs.

Top Level Domains

How to Block Top-Level Domain (TLD) in Microsoft 365? | A Step-by-Step Guide

Step 1: Access the Exchange Admin Center

Access the Exchange Admin Center (EAC) in Microsoft 365 to start the process. The EAC is where you manage mail flow rules where specific TLDs can be blocked. Check steps:

Sign in to Microsoft 365 Admin Center

Go to the Microsoft 365 Admin Center and sign in with your admin credentials.

Check the screen’s left side and select “Exchange” from “Admin centers” to open the EAC.

Step 2: Create a New Mail Flow Rule

Mail flow rules allow you to apply specific actions to emails based on various conditions. You must create a rule that identifies emails from the specified TLDs and blocks them.

Go to Mail Flow

In the EAC, select “Mail flow” from the left-hand menu.

Create a New Rule

Click the “+” icon and select “Create a new rule.”

New Mail Flow Rule

Step 3: Configure the Rule Conditions

It’s time to define the conditions that the rule will apply to. In this case, you will set conditions to identify incoming emails from particular TLDs.

Name the Rule

Give your rule a name, such as “Block Specific TLDs.”

Set Conditions

Click on “Apply this rule if…” and select “The sender’s domain is…”

Configure the Rule Conditions

Specify TLDs

Enter the TLDs you want to block, such as “.ru,” “.xyz,” or “.info.” You can add multiple TLDs by separating them with a semicolon.

Step 4: Define the Action

Now that the rule is set to identify emails from the specified TLDs, you need to define what action to take. The most common action is to reject the message.

Select an Action

Select “Do the following…” and open “Reject the message with the explanation.”

Customize the Explanation

Enter a message that will be sent to the sender when their email is rejected, such as “Emails from this domain are not accepted.” Or, it could be anything you want.

Define-the-Action

Step 5: Set Exceptions (If any)

Sometimes, you want to allow emails from one or more senders within the blocked TLDs. You can set exceptions to your rule to permit these emails.

Add Exceptions

Click on “Except if…” and define the conditions for exceptions. For example, you can allow emails from specific addresses or domains within the blocked TLDs.

Step 6: Save & Activate the Rule

After configuring the conditions, actions, and exceptions – it’s time to save & activate the rule.

Save the Rule

Click “Save” to create the rule.

Activate the Rule

Ensure the rule is enabled by checking the status in the list of mail flow rules.

Define-the-Action

Step 7: Test the Rule

You must test the rule to ensure it’s working as intended. Send test emails from the blocked TLDs and verify that they are rejected with the specified explanation.

Send Test Emails

Use email addresses with the blocked TLDs to send test emails to your organization.

Verify Rejections

Check that these emails are rejected and that the sender receives the rejection message.

Monitoring & Maintenance

Blocking TLDs is not a one-time task. Regular monitoring is essential for your email security.

Monitoring Maintenance

Review Logs

Regularly review email logs to identify any unusual patterns or missed threats.

Update Rules

As new TLDs become problematic, update your rules to include them.

Check Exceptions

Periodically review exceptions to ensure they are still necessary and do not pose security risks.

Best Practices for Managing Mail Flow Rules

To maintain a robust email security posture, consider the following best practices:

Keep Rules Simple

Avoid overly complex rules that are difficult to manage.

Document Changes

Keep noting any changes to your mail flow rules for future reference.

Stay Informed

Keep up-to-date with the latest email security threats and trends to adjust your rules accordingly.

Conclusion

Blocking specific TLDs in Microsoft 365 is a powerful way to enhance your email security. Follow these steps to effectively block unwanted emails from malicious TLDs. This will reduce the risk of spam & phishing attacks. Monitor your mail flow regularly for security certainty.

Do you need any help with email security?

Connect with us (Leasepacket) – we offer all kinds of security & server solutions and expert support. Contact us to get a quote!

FAQs

Q1. How do I access the Exchange Admin Center in Microsoft 365?

Sign in to the Microsoft 365 Admin Center, go to “Admin Centers,” and then select “Exchange” to open the Exchange Admin Center.

Q2. Can I block multiple TLDs at once in Microsoft 365?

Yes! You can block multiple TLDs by separating them with a semicolon while selecting TLDs in the rule conditions.

Q3. What happens to emails from blocked TLDs?

Emails from blocked TLDs will be rejected, and the sender will receive a rejection message that you put in.

Q4. Is it possible to allow some emails from blocked TLDs?

Why not! You can set exceptions to allow emails from specific addresses or domains within the blocked TLDs.

Q5. How can I test if my rule for blocking TLDs is working?

Send test emails from addresses with the blocked TLDs to your organization and verify that they are rejected with the specified explanation.

Q6. Why is it important to regularly update & monitor mail flow rules?

Regular updates & monitoring ensure your email security remains effective against new threats and that no legitimate emails are blocked unnecessarily.

Q7. What if I need help with my email security?

You can connect with Leasepacket. Leasepacket offers all kinds of security & server solutions and expert support. Contact us to get a quote!