DNS

In this post, you will learn what BIMI is, how it works, and the benefits it brings to your domain, including increased trust and brand visibility. We live in a time where most first impressions happen online, and emails are usually the first touchpoint. The problem is, inboxes are crowded, and getting someone to notice your message isn’t easy. That’s exactly why BIMI (Brand Indicators for Message Identification) was created. It gives companies a simple way to show who they are and build trust the moment their email lands. ...

This blog post explains how an MTA-STS policy works and how to implement it on GitHub Pages. MTA-STS (Mail Transfer Agent Strict Transport Security) is a security protocol that enforces the use of secure TLS connections for inbound email communication. It helps protect your domain from TLS downgrade and man-in-the-middle attacks by ensuring that incoming emails are encrypted with TLS when delivered to your mail servers. When an external mail server (SMTP client) attempts to send email to your domain, it checks your MTA-STS policy to determine whether TLS encryption must be enforced. ...

In this post, you will learn how to enable and use SMTP DANE with DNSSEC in Exchange Online. While outbound SMTP DANE with DNSSEC in Exchange Online has been enabled since 2022, Microsoft is has rolling out inbound SMTP DANE with DNSSEC in Exchange Online since late 2024. For a deeper understanding of DNSSEC and DANE, take a look at my earlier blog post. How SMTP DANE with DNSSEC works SMTP DANE is a security protocol that uses DNSSEC to verify the authenticity of TLS certificates used for securing email communication. It helps protect against attacks such as TLS downgrade and man-in-the-middle attacks by ensuring that the certificates and encryption settings used in mail server communications are authentic and trustworthy. ...

This blog post explains the role and benefits of ARC sealing. ARC (Authenticated Received Chain) is an email authentication protocol that preserves the authentication results of an email as it travels through multiple intermediaries, such as forwarding services. This allows your recipients to accept the ARC Seal from your relaying or intermediate server. Using ARC helps organizations handle the complexities of email authentication, especially when emails are forwarded. ARC involves multiple servers working together based on mutual trust. In this blog post, we will explore the basics of ARC, how it works, and the benefits it provides. ...

In this post, you find out how DNSSEC and DANE cooperate, and learn how to set up DANE TLSA DNS records. DNSSEC (DNS Security Extensions) The domain name system (DNS) is the phone book of the Internet: it tells computers where to send and retrieve information. Unfortunately, it also accepts any address given to it, no questions asked. DNSSEC adds a security layer to this phonebook. It uses digital signatures to make sure the information in the phonebook can be trusted and hasn’t been tampered with. It’s like putting a lock on the phonebook to prevent DNS spoofing. ...

In this post, I will share my best practices for getting a handle on your SPF record. Why it makes sense to have a good SPF procedure in place In a previous blog post, I explained the limitations of SPF and how it works with DKIM and DMARC. It’s crucial to have a well-structured SPF procedure to avoid future problems, especially since exceeding the DNS lookup limit of 10 can cause issues, such as: ...

In this post you will learn to understand how the DNS protocols SPF, DKIM and DMARC work together to protect your domain from phishers and spammers. Why deploy SPF, DKIM, and DMARC? SPF, DKIM, and DMARC are critical email authentication protocols that help prevent email spoofing, phishing attacks, and domain impersonation for outbound email. Enabling these protocols together strengthens your domain’s email authentication mechanisms, improves security, and builds trust with your recipients by ensuring that email sent from your domain is legitimate and trustworthy. ...