Editing Training 2022 Linux team/ (section)

==Training  SSLCertificate Training Part 2. Dated 11 Feb 2022 - Tetra Support Staff - Biswajit Banerjee==

{{#ev:youtube|FlwB8lxHzh4|640}}

'''Video summary:''' "SSLCertificate Training Part 2" -- a clear English-language session on commercial SSL certificate generation and deployment, contrasted with the Let's Encrypt process covered in an earlier (unrecorded or untranscribed) session. Explains that every certificate is one of three types: domain-specific, wildcard (e.g. `*.tetrain.com`, valid for any subdomain), or the much rarer IP-based certificate, and that mismatched domains/certs produce browser "not certified" warnings. Walks through the commercial issuance flow using real client examples (CareIndia, News Nation): generate a CSR (Certificate Signing Request) either via a vendor's web portal or with OpenSSL locally, submitting identifying details (common name = the domain, organization, country, state, city); a CSR always generates a paired private key that must be preserved exactly -- regenerating the CSR changes the key and invalidates any certificate already tied to it, which is why the presenter deliberately avoids re-generating one mid-demo. Covers domain-ownership verification methods vendors use before issuing (hosting a verification file/key on the site, or emailing the domain's registered admin contact for click-to-approve), and that a completed order returns multiple files -- the actual domain certificate, plus intermediate and root certificates that must be chained together correctly on deployment (matching the `chain.crt` + main cert pattern used in the team's Let's Encrypt process). Distinguishes Zimbra's admin-console CSR generator (used only to *generate/request* a certificate, since Zimbra's UI doesn't understand automated ACME renewal the way an Apache/Nginx site can) from `certbot`, which Tetra uses only in "get cert" (not full install) mode against Zimbra since Zimbra isn't a web server Certbot recognizes -- versus a plain Apache/Nginx-backed site (demoed on Beetel's server), where Certbot can both obtain and fully deploy the certificate automatically. Ends by assigning homework: come prepared for the next session to deploy a commercial certificate manually on Apache (matching cert, key, and intermediate cert), with the presenter stressing self-directed exploration as essential for Linux administration skill-building.