title: S/MIME Mail Encryption with Self-Signed Cert
body: <p>We have a domain with a local CA. Once upon a time there came a projet with a must to protect project-emails with S/MIME-Encryption. We issue the certs, setup the mail clients, everything goes fine. Then comes a situation, there are external emails in the project communication. External developers, Clients, etc.
  For example one of a Clients have thier Certificates from a Trusted Public Issuer.</p>
  <p>Q1: Does the Self-Signed and Public-Trusted Certs have any difference? Does the Public-Trusted-Cert any advantage in this scenario?</p>
  <p>Q2: Chase we install a Public-Trusted-Domain-Cert on the CA and re-issue the S/MIME-Certs, will the new Certs &quot;better&quot;? Will they receive any advantage in this scenario?</p>