pmichelazzo wrote:
1) Need I to buy a SSL certificate to every domain that I have configured, to remove that not trusted certificate page from Firefox/Chrome?
Buy one for all domains should be easier.
pmichelazzo wrote:
2) The certificate can remove too the "bad certificate" message window when I client use the Outlook?
Bought SSL certificate doesn't have this issue. But it sometimes depends on mail clients, some old mail clients don't recognize SSL certificate signed for all sub domains. e.g. *.example.com.
pmichelazzo wrote:
3) Cheap certificates can be used for it, like a PositiveSSL, InstantSSL or EssentialSSL?
Yes.
pmichelazzo wrote:
4) If I buy a certificate, can I move it to a new server with the Pro version of IredMail?
SSL certificate depends on your server hostname.