Monthly Archives: February 2020

Office 365 Joins ARC

Microsoft is the latest prominent name to adopt the Authenticated Received Chain (ARC) email protocol.  The ARC standard is now available for every Office 365 hosted mailbox. Already used by Google (Gmail, G Suite, Groups) and other email providers, the continued adoption ARC improves email delivery and security.

What Is ARC?

ARC is a new protocol designed to provide an authenticated “chain of custody” for emails. Essentially, this initiative requires that each forwarding email system handles the message in a standard way to preserve the DKIM wrappers.  This allows each inbox provider in the chain to see what other intermediaries have handled it along the way and verify the DKIM signature of the message at each step throughout the delivery process.

ARC leverages the DMARC and DKIM email authentication standards to help fight email spoofing and improve email delivery for forwarded messages.  Prior to ARC, the chain of custody may or may not have been preserved for forwarded emails, resulting in legitimate mail being rejected.  With the implementation of ARC,  email forwarded to Office 365 will be more likely to be delivered as DKIM signatures will be preserved.

Seeing the Benefits of ARC

RFC 8617, specifies the ARC standard for inbox providers, but, what does that mean for business senders?  First, you need to adopt the basic email deliverability standards – SPFDKIM and DMARC.  If you have not already read it, MxToolbox has a great guide to setting up these protocols.  Once you have SPF, DKIM and DMARC setup, inbox providers that have adopted ARC will automatically process your email appropriately.  

MxToolbox Delivery Center provides everything you need to manage the on-going maintenance of email delivery.  Learn more about Delivery Center and how we can help you with email deliverability!

BIMI Monitoring has arrived

MxToolbox is happy to announce additional support for BIMI in the form of BIMI record monitoring.  Now, you can be confident that all your important email deliverability records are properly configured and constantly monitored by our experts.

What is BIMI?

BIMI is an email delivery standard that works with other standards (SPF, DKIM and DMARC) to publish an image or logo on an end-user’s email box when an email comes from you. BIMI helps your email recipients feel confident that an email is legitimately from you and helps to protect your brand from use in fraud and phishing.

How does BIMI work?

First, you need to have SPF, DKIM and DMARC properly setup.  Next, you publish a BIMI DNS record that defines your preferred logo image.  Then, when you send email to a user on a BIMI-Supported inbox provider, like Yahoo! and, in Summer 2020, Google, the inbox provider you have a chance of displaying your logo.

Inbox providers will check for DMARC compliance on every email.  If the email passes DMARC tests, then this inbox provider will check for a BIMI record.  If a valid BIMI record is found, then the inbox provider will display your logo next to the email.  As these checks happen on each email, you need to be sure that your email is both passing DMARC and that your BIMI record is accessible every time you send email.  With a BIMI logo next to every email you send, your customers will be reassured that each email is a legitimate communication from you and have your brand top of mind.

MxToolbox BIMI Monitoring

MxToolbox is expanding our support for BIMI by announcing the inclusion of BIMI record configuration monitoring as part of MxToolbox Delivery Center.  You can already test your BIMI record with our Supertool, but now we offer integrated alerts when BIMI is non-accessible or misconfigured.

Since BIMI is dependent on SPF, DKIM and DMARC, MxToolbox highly recommends that you adopt tools, like Delivery Center, to help you setup and maintain these technologies while also monitoring your your day-to-day DMARC compliance.  MxToolbox Delivery Center leverages our email expertise to improve your email deliverability and allows you to focus on running your business.  Adding BIMI to a tool like Delivery Center will help improve your email delivery and improve the visibility of your brand.

ARC Protocol – Getting your email delivered

Recently, RFC 8617 established the Authenticated Received Chain (ARC) Protocol, a new and powerful email authentication and security standard that allows legitimate forwarded emails to be delivered without any issues.   ARC has been in testing for several years with Google and another inbox provider to transform the theoretical solution into a full-fledged standard.

What is ARC?

ARC allows mail handlers (email servers) to preserve a “chain of custody” that shows where the respective message originated and all subsequent handling entities via authentication data when forwarding emails. To get more specifics about the ARC protocol, click here.

Before ARC, a forwarded email would no longer pass DKIM alignment because there was no standard for preserving the original and subsequent DKIM signatures.  An unaligned message might then fail DMARC and be rejected by the final inbox provider and never reach your customer’s inbox.

The ARC protocol establishes a standard for preserving DKIM alignment when a message is forwarded.  This helps these messages look less suspicious to the receiving inbox providers by ensuring emails that are forwarded pass authentication and avoid being labeled as spoofed messages. 

Why is ARC important?

ARC becoming a standard applied to all inbox providers is highly important for your email deliverability. With ARC, if your business forwards email and has implemented DKIM, your email chain of custody will no longer break, resulting in higher delivery rates.  While SPF alignment breaks under most message forwarding instances, DKIM breaks when emails pass through forwarding services that modify content involving a DKIM signature. Even if the email fails SPF and DKIM validations, the inbox provider can choose to validate the ARC standard.

It is imperative that your business email implement DKIM as soon as possible to improve email deliverability and leverage the benefits of ARC.

ARC Enables more DMARC Adoption

The creation of the ARC standard shows continued support for the DKIM, SPF and DMARC standards that are the basics for email deliverability.  ARC allows messages that have been forwarded via mailing lists, list servers, and email gateways to pass DKIM authentication and not break during delivery.  DKIM is integral to achieving DMARC compliance, so the ARC standard also allows more senders to pass strict DMARC policies.  Strict DMARC block non-DMARC compliant email to improve your company’s overall email deliverability by reducing the threat of fraud and phishing using your domain.

What do I need to do to take advantage of ARC?

The first steps to leveraging ARC involve the adoption of basic email deliverability standards – SPF, DKIM and DMARC.  If you have not already read it, MxToolbox has a great guide to setting up these protocols.  Once you have SPF, DKIM and DMARC setup, inbox providers that have adopted ARC will automatically process your email appropriately.

MxToolbox Delivery Center provides everything you need to manage the on-going maintenance of email delivery.  Learn more about Delivery Center and how we can help you with email deliverability!