Software & Apps MS Office How to Block a Domain in Outlook Mail on the Web Block domains using blocked senders or email rules by Heinz Tschabitscher Writer A former freelance contributor who has reviewed hundreds of email programs and services since 1997. our editorial process Heinz Tschabitscher Updated on November 15, 2019 MS Office Outlook Word Excel Powerpoint Tweet Share Email Outlook Mail on the web makes it easy to block messages by individual senders from showing up in your inbox folder. For even more effective spam blocking, ban entire domains as well. Instructions in this article apply to Outlook.com and Outlook Online. Block a Domain in Outlook Mail on the Web To have Outlook Mail on the web reject messages from all email addresses at a specific domain: Select Settings (the gear icon ⚙️). Select View all Outlook settings. Select Mail > Junk email. In the Blocked senders and domains section, select Add. Type the domain name you want to block, then press Enter to add the domain to the list. The domain name appears after the @ in an email address. For example, if the recipient is firstname.lastname@example.org, the domain is clientcompany.com. Select Save, then close the Settings dialog box. When you get an email from that domain, it's automatically diverted to the Junk Email folder. Block a Domain in Outlook Mail on the Web Using Filters To set up a rule that automatically deletes certain emails — such as all emails from a domain you cannot block using the blocked senders list — in Outlook Mail on the web: Select Settings. Select View all Outlook settings. Select Mail > Rules. Select Add new rule. Name the rule, then select the Add a condition dropdown arrow and choose Sender address includes. In the Enter all or part of an address text box, enter the domain you want to block. Select the Add an action dropdown arrow and choose Mark as Junk. Optionally, to specify conditions that prevent an email from being deleted even though it is from a blocked domain (or sender), select Add an exception, then choose From. Enter the email address you want to allow. Select Save to finish. Close the Settings dialog box. Any email from the domain you've defined in the rule automatically goes to the Junk Email folder. Only email addresses you've specified in the exclusions are allowed in your inbox and won't be diverted to the Junk Email folder.