At 25 October, 2020 R. Diez wrote: > > I am too afraid, I would not expose any such port on the Internet. Who knows > if the mail server stays months without an update. If I am to recommend or > implement any such mail server solution to a small business, I would insist > that the e-mail server is not exposed at all on the Internet.
Setting and forgetting any server/service to run unpatched for months is generally a bad idea. I presume that you won't be maintaining this for them long term -- why not just point them at a hosting service like google apps, and let google keep things up to date?