Understanding my VPS (SSL certificates and mail server)

Hi everyone,

I am trying to move on with the acquisition of knowledge to what digital technology is related, but I have doubts concerning the management of my own VPS.

Wait a minute! Am I managing my own VPS with little to no knowledge whatsoever about what the heck I am really doing with it? Kind of. I mean, I do have acquired a VPS, and I can kind of manage some parts of it… but I don’t know if I can truly call management as such what I’ve done so far with it…

Now, why do I have a VPS? Well, that’s a good question which a friend of mine — a great programmer — has made me reconsider, but let us get down to it in some other topic, if it is OK with you guys.

At the moment, I am trying to understand how the whole VPS thing works and how I could learn to be better and better at its management every day. So far, I am reading my VPS provider’s blog and the PLESK official site to get a general understanding, but (first question), would you guys know any other information source to get really good tat managing a Plesk-based VPS?

Now, back when I was studying communication at college, there were two main paths to what computing science was related: “networks engineering” and “systems engineering”. 15 years later, I kind of understand that systems engineers create systems — generally thru code — and networks engineers are the ones who learn how to deal with all of these concepts that I am now trying to understand in depth (SSL, FTP, VPS management…). Second question: Does that make any sense or am I any right so far ? I mean, wanting to learn to program my own stuff is one thing (one path), but trying to understand “how internet works” — or, rather, how things work in internet — is a completely different one, am I right?

Third question

I can access my VPS thru and access point set upon https://xxx.yyy:zzzz, where xxx is a domain name of mine, yyy is its extension and zzzz is the port I use to access it. That VPS is protected by a paid SSL certificate (Rapid SSL, in this case). This SSL certificate not only covers the VPS but also the web hosted at https://xxx.yyy and the mail server (both for incoming and outgoing email) associated to that same VPS (which I can config in my mail client thru mail.xxx.yy). Does that make any sense so far?

Fourth question
Now, within that VPS, I’ve got plenty of other domains associated. Let’s take one of them as an example and let’s call it aaa.bbb, where aaa is the name and bbb is the extension. Let’s say that this domain has its own paid SSL certificate associated (also Rapid SSL). Now, that SSL certificate only protects the web hosted at https://aaa.bbb, right?

Fifth question

Then, as I want to config aaa.bbb’s mail in my mail client (Apple’s mail default application in this case), both the incoming and the outgoing mail server no longer should be mail.aaa.bbb — which is what I did before having a paid SSL certificate associated to my VPS —, but I should have mail.xxx.yyy as mail server (both incoming and outgoing) in such a way that the connection among my VPS’ mail server and my mail client (Apple’s) would be protected by the xxx.yyy’s SSL certificate. Does that still make sense?

Sixth question

However, Rapid SSL won’t cover subdomains, so as I want to enter my email thru a web browser (let’s say webmail.aaa.bbb), this subdomain should be configured in my VPS to be covered by a Let’s Encrypt SSL certificate (the one that is free), which provides wildcard coverage (*.aaa.bbb). Still right?

Well, I don’t know if I should’ve broken down this looooong post into smaller chunks, but, firstly, I wanted to be thorough and, secondly, I am new at this kind of communities so I don’t know if it is better to be thorough on just one post or rather having my inquiries broken down in smaller pieces. Grateful if you may let me know as well.

Thanks so much in advance and see you around :slight_smile:

Cheers!