[CentOS] mail issue help and need good mail server

> Thank you for your helping
>
> but why user keeps downloading mails what he downloaded before?
>
> I check the mail client setting and it works fine
>
> If it is not server control, any hints about this problem
>
Here's one example: me. When I'm not at home, I read my email via webmail.
I could, I suppose, d/l it *without* deleting from the server. Then, when
I get home, I fire up t-bird, and d/l all my mail, this time deleting it.

I might assume that some folks d/l frequently, but do not delete from the
server, thus saving space on their own system, but storing everything on
the server.

        mark