How can you ensure all subdomains of spamsender.com are blocked?

To effectively block all subdomains of spamsender.com, configuring a new Blocked Senders policy set to Block Sender is the appropriate action. This approach utilizes the wildcard feature, allowing you to specify a pattern that matches all subdomains under spamsender.com. By using this policy, you ensure that any email coming from addresses such as mail.spamsender.com, news.spamsender.com, or any other subdomain will be intercepted and blocked by Mimecast.

The mechanics of this policy enable robust spam filtering and management, enhancing the protection against malicious or unwanted emails that may originate from various subdomains associated with a known spam source. The ability to block an entire domain, including its subdomains, is essential in maintaining email security and preventing phishing attempts that may exploit less obvious addresses under the same domain umbrella.