Hello,

Can you please help with the decision of choosing the right solution for technical needs.

The need:

To have secured email communication.
All the emails should be encrypted during the process of sending.
All the emails should be encrypted on the email server itself.
Encryption send/receive when sending on same email domain.
What can be done when sending outside of domain?
Web access and local access in office when using M.Outlook or Thunderbird (some computers on Linux Mint).

Email server for team of 10-15 person.
Will need around 15-20 email addresses, maybe more later.

What email server would you suggest us?
Will we obtain our security goal if will use some online services, or if will rent a dedicated server or vps at our local hosting or internet provider?

Thank you in advance.