Looking for adding a subdomain to an existing certificate? We can help you add it.

Certbot is the client that fetches a certificate from the certificate authority (Let’s encrypt).

We can add the subdomain to the existing certificate, by running a single command.

At Bobcares, we often get requests from our customers to add an SSL certificate for subdomain as part of our Server Management Services.

Today, let’s get into the details on how our Support Engineers add SSL for a subdomain.

Include Certbot certificate for a subdomain

Certbot is a free, open-source software tool that enables Let’s Encrypt certificates for securing the websites.

Generally, we install the certificate for the default domain and www.domain name.

Sometimes customers will add new subdomains later under a domain. The existing SSL certificate won’t get effective to this subdomain which in turn causes security warnings.

However, It’s an easy task to add the newly created subdomain to the certificate.

Let’s see how our Support Engineers help the customers to fix this problem.

How to generate Certbot certificate for a subdomain

At Bobcares, where we have more than a decade of expertise in managing servers, we see many customers face problems in including a subdomain to an existing certificate.

Now, let’s see how our Support Engineers fix this problem by including existing SSL certificates to subdomains.

Recently one of the customers approached us for adding an SSL certificate for the newly created subdomain. The customer already had a Let’s Encrypt certificate issued using Certbot for the domain and www.domain name.

Unfortunately, this certificate was not applicable to the newly created subdomain which causes a security warning while accessing the subdomain.

To install the certificate for the subdomain. We need to install it including the domains that are already present. Thus we use the command.

certbot -d domain name,subdomain.domain name,www.domain name --expand

If the user is not using the Apache or Nginx plugins, we have to include certonly on the command line.

certbot  certonly  -d domain name,subdomain.domain name,www.domain name --expand

In general, while running the command we have to include every domain name and subdomains that wanted the certificate. If we forget to do so, the excluded domain will not have the certificate. Thus will have to rerun the command including the domain.

After running this command the SSL certificate was included for the subdomain.

[Need any assistance to add the subdomain to the existing certificate? – We’ll help you]

Conclusion

In short, Certbot helps to generate the certificate for securing the website. However, the newly added subdomain may not get the advantage of the existing SSL certificate of Certbot. Today, we saw how our Support Engineers help the customers to Certbot generate a certificate for the subdomain.