Prevent delivery from internal adresses anywhere except to internal addresses
I have zimbra 8 FOSS installation and internal domain mail.local. External mail is received with external accounts in user
preferences. Each user has another persona with external email (e.g. @mail1.com) -
each user has two addresses, i.e email@example.com and firstname.lastname@example.org.
@mail.local is for confidential internal mails.
Is it way to prevent outgoing mail from addresses @mail.local to any address except @mail.local, but permit @mail1.com to any addresses ?
email@example.com -> firstname.lastname@example.org --- may cause an error or delivery failure message
email@example.com -> firstname.lastname@example.org --- everything OK
email@example.com -> firstname.lastname@example.org --- everything OK