Whether you're running a personal website or managing a large network with countless domains, one thing is clear: trust is essential online. At the core of that trust is a security process called Domain Control Validation (DCV). This step is crucial for getting SSL/TLS certificates, which show that you really do control the domain you're looking to secure.
DCV plays a key role in how browsers and users figure out which websites are trustworthy. Without it, Hypertext Transfer Protocol Secure (HTTPS) wouldn’t carry any weight. In this post, we’ll break down what DCV is, how it works, why it matters, and how new industry standards are changing the way we handle domain validation.
What is Domain Control Validation?
Domain Control Validation, or DCV, is an important step that needs to happen before a Certificate Authority (CA), such as GlobalSign, can issue an SSL/TLS certificate. Essentially, it verifies that the person or organization asking for the certificate actually has control over the domain name in question.
This process is a vital security measure. Without DCV, anyone could request a certificate for any domain, which could lead to impersonation of legitimate websites, data theft, or website phishing. DCV helps prevent this by ensuring that only the actual domain owners or those who manage the domain can get these certificates issued.
How Domain Control Validation Works
Domain Control Validation can be completed using a few different methods, all of which are recognized by industry bodies like the CA/Browser Forum. The most common approaches include:
- Email-based validation, where a confirmation email is sent to a pre-approved contact address associated with the domain (like admin@yourdomain.com).
- DNS-based validation, which involves adding a specific TXT record to your domain’s DNS zone to prove ownership.
- HTTP-based validation, where a unique file is placed on a publicly accessible part of your website so it can be retrieved by the CA.
Each method has its own advantages. For example, DNS-based validation is great for automated systems and headless environments, while email validation is a popular choice for simpler setups. HTTP validation works well for developers and web admins who have easy access to their servers.
When and Why You Need DCV
DCV is required whenever a certificate is issued for a domain — whether it’s the first time or during a renewal. It’s also necessary when reissuing a certificate, adding new domains to a multi-domain certificate (SAN), or securing a wildcard domain.
Even if you’ve validated a domain before, that validation doesn't last forever. The CA must periodically re-confirm that you still control the domain, ensuring that certificates remain trusted and current. This is especially important for large organizations that rely on automation or have frequent certificate updates.
What is a Domain Reuse Period, and What’s Changing?
Once a domain has been validated, that validation can be reused for a period of time, this is known as the domain reuse period. It helps reduce the need to repeatedly validate domains for each certificate request, which makes life easier for IT teams and supports efficient automation.
However, the length of this reuse window is changing. The CA/Browser Forum passed Ballot SC-70 in April 2025, which will gradually reduce the allowable domain reuse period from 398 days to just 10 days by 2028. The goal is to tighten security by ensuring that validations remain accurate and current, minimizing risks that might arise from outdated validation data.
This shift won’t impact all organizations immediately, but it’s something to prepare for. If your current certificate management workflows rely on long reuse windows, they’ll need to be updated. Automation and API-driven validation will become even more important in this new environment.
Why DCV is So Important for Internet Security
Trust in HTTPS begins with the CAs that browsers and operating systems choose to trust — but that trust only holds if CAs rigorously verify who they issue certificates to. DCV is a key part of that process. It ensures that certificates are only issued to verified domain owners, and that users who visit a secure site are connecting to the intended organization and not an imposter. DCV acts as the vital bridge between the root of trust and the digital identities we rely on every day.
When DCV is handled correctly, it ensures that your specific domain is verified, reducing the prevalence of its use in phishing attacks, domain impersonation, and man-in-the-middle attacks, reducing avenues of impersonation to using similar but fundamentally different domain names in the hopes of tricking users – but preventing them using your exact domain name. It protects end-users, website owners, and the broader digital ecosystem by making sure that only authorized parties can secure and represent domains.
It also supports the integrity of browser trust stores. Browsers trust CAs to follow strict validation procedures, and DCV is one of the cornerstones of that trust model. If CAs didn’t rigorously validate domain control, HTTPS indicators (such as the padlock icon) would become meaningless.
Getting DCV Right Matters More Than Ever
Domain Control Validation may not get much attention outside of IT and security cliques, but it plays a pivotal role in keeping the web safe. Without DCV, the system of trust that enables secure communication over the internet simply wouldn’t function.
As standards evolve and validation windows shrink, it’s more important than ever to stay informed and make sure your DCV processes are solid. Whether you’re running a small website or managing certificates at scale, understanding DCV (and getting it right) is essential.
