ARC, or Authenticated Received Chain, is an email security standard that preserves the original email authentication information as it passes through intermediary servers. Trusted ARC sealers are email services that provide valid and trustworthy ARC signatures, ensuring that your emails arrive at their destination unaltered.

Setting up trusted ARC sealers is like adding an extra layer of defense to your email security strategy. Microsoft Defender for Office 365 allows you to configure trusted ARC sealers for your custom domains. This feature lets admins add trusted intermediaries in the Microsoft 365 Defender portal, allowing Microsoft to honor ARC signatures from your list of trusted intermediaries to help authenticate the message .

So, why should you care about ARC sealers? Well, without them, your legitimate emails could fail authentication when they pass through an intermediary server that makes modifications to the header and content. By configuring trusted ARC sealers, you can ensure that your emails are properly authenticated and delivered to their intended recipients.

In conclusion, ARC sealers are an important part of any email security strategy. By configuring trusted ARC sealers, you can improve your email deliverability and ensure that your messages are properly authenticated. So, seal the deal with ARC sealers and give your emails the protection they deserve.