I would like to get mails on my smartphone.
Now i have configured my firewall and id works fine.
But i would also like that all other users are not able to acces via IMAP from extern.
I have disabled extern IMAP in the Zimbra admin gui but all users are able to acces there mails from external.
How can i prevent users from acces there mails from external ?
And how can i prevent users from sending mails from external ?

I think this is a big security problem.