In his &quot;overview of features&quot; he is missing one very interesting and valuable security gain when you host your own mail server:<p>- local mail delivery does not traverse any network<p>So if you are user A on a mailserver and your wife&#x2F;friend&#x2F;uncle is user B, when you send mail to them that mail is simply a local copy operation (provided they don&#x27;t POP or IMAP it to a local mailtool).<p>That&#x27;s pretty interesting, I think.<p>It may interest you to know that no piece of rsync.net company email has <i>ever</i> traversed a network - everyone logs in via SSH and uses (al)pine and all internal mail is just local copy ...