I have a Posix mail server that serves as a gateway to an MS Exange server. The Posix server contains aliases (stored in openldap) that match the users in the MS Exchange server. So somebody could send an e-mail to j...@example.com (the MX register for example.com is my Posix server), this would reach this Posix server that would check for the alias in the ldap directory. This would retrieve j...@corporative.example.com whose mailbox is in the MS Exchange Server.
Since I'm new to Posix (and my duty is to learn how this system is working), I think that maildrop performs a DNS request for the MX register for the domain corporative.example.com and then an SMTP connection is established between Posix and MS Exchange, that eventually would deliver the e-mail to j...@corporative.example.com in his local mailbox. But I'm not sure about how this works. This is how this is configured in main.cf: -------------------------------------------------------------------------------- myhostname = some.example.com myorigin = /etc/mailname mydestination = some.example.com, some, localhost.localdomain, localhost relayhost = relay_domains = corporative.example.com otherdomain.com mynetworks = 127.0.0.0/8 10.120.200.0/24 virtual_alias_maps = ldap:valiases valiases_server_host = localhost valiases_search_base = ou=alias,dc=example,dc=com valiases_result_attribute = maildrop virtual_transport = maildrop virtual_mailbox_base = /var/vmail/ virtual_mailbox_maps = ldap:ldapvirtualmap ldapvirtualmap_server_host = localhost ldapvirtualmap_server_port = 389 ldapvirtualmap_bind = no ldapvirtualmap_search_base = ou=users,dc=example,dc=com ldapvirtualmap_result_attribute = mailbox -------------------------------------------------------------------------------- The MX register for some.example.com is the MS Exange server. Since virtual_alias_domains is not defined, I suppose that every time an email is sent to someb...@example.com, a lookup in the ldap directory is performed. If I set virtual_alias_domains to example.com (or any other domains I serve), wouldn't this be enough to reject everything that's not directed to the domains I serve? I must say that everything works ok but I don't know why there's no need to set virtual_alias_domains.
