How does domain verification for a DV SSL work?

DV SSL can be issued in minutes with minimal effort on your part.

One of the biggest advantages of Domain Validation SSL certificates is how rapidly they can be issued. Whereas OV and EV may require a few days for validation, you can get a DV certificate verified and issued in just minutes. For Domain Validation to be completed Comodo simply needs to complete verification that you own the domain. That's it. Simple.

Email Validation

The easiest, most straightforward way to verify you own the registered domain is via email. Comodo will look at the WHOIS record for your website and send an email to the listed email address. Simply respond to the email in the affirmative and you've finished validation.

What if my email isn't on the record?

In the event that your email address isn't the one on the record, you're not out of luck. Comodo will also send the authentication email to one of five pre-approved addresses.

File-Based Authentication

If email-based domain authentication won't work, there is also file-based authentication. Basically, Comodo will supply you with a text file. All you have to do is upload it in your root directory and Comodo will verify it. Boom. You're done!

CNAME-Based Authentication

There is one final way that Comodo can complete domain authentication. With CNAME-based validation Comodo will supply you with two unique hashes, one using the MD5 algorithm and one using SHA-1. You must enter them in your CNAME DNS Record like so:

"<MD5 hash>.yourdomain.com CNAME <SHA-1 hash>.sectigo.com."

Once you've done this Comodo will complete the SSL domain verification and you're done with validation.