I am hoping to clear up some confusion I have regarding the use of Let's Encrypt for an internal site/application. I have not been able to find this information elsewhere.
I want to use Let's Encrypt paired with Certbot to allow the use of SSL on an application.
- Does Let's Encrypt or Certbot require internet access to perform any part of their job? The application will need to be able to run normally even if internet access is down. From what I can gather the only part that requires internet connectivity is for generating new certs when the 90 day period is drawing to an end.
- Let's Encrypt requires a valid domain. Per their website "for any server that uses a domain name, like web servers, mail servers,...". I'm rather ignorant to what it means to have a valid domain. If I have Apache on my server that already hosts other web applications does any domain name I set up with Apache count or do I need to purchase a domain name?
- In the previous question I mentioned other applications are going to be on this server. These do not require SSL. If I set up Let's Encrypt and Certbot on my server does that mean that these applications have SSL available or is it specific to the domain(site) name used to set it up? Will any of these other applications need modification if a separate application is using SSL?
- Hypothetically lets say I want to get a root certificate but instead of using this with Certbot I want to create and use a set of intermediate keys. Is this possible? Would these intermediate keys need to by altered each time we create a new root key?
I apologize if any of my questions are ignorant, my knowledge of this kind of stuff is very limited. That said, there may even be better options to accomplish what I need so I am open to suggestions. I opted for Let's Encrypt over a self signed cert because with this solution I would not need to add a CA to each client machine that needs access.