Hello,

I will explain what I need to know.

I have 3 Servers:

1) One of them is just a Domains Server.

2) The other two are Mailboxes Servers. They have the email accounts for all the Domains from the first Server.

All these mailboxes' POP and SMTP are accessed through the Server address:

mail.domainnamea.com.

mail.domainnameb.com.

mail.domainnamec.com.

and so on.

If someone who accesses my Roundcube, fill the Server field with any other POP Server name elsewhere, he will read those emails. How to avoid it, so that only mailboxes in one of my two Mailboxes mentioned above can be accessed?

Thanks a lot.