Managing Domains
Creating a Domain Alias
If you have a domain domain.com and you want the domain example.com to be an alias for it, so that sending mail to user@example.com is the same as sending mail to user@domain.com (delivered to the same mailbox), you can designate example.com as a domain alias when creating the domain. This example assumes domain.com already exists, but example.com does not.
zmprov cd example.com zimbraDomainType alias zimbraMailCatchAllAddress @example.com zimbraMailCatchAllForwardingAddress @domain.com
Relaying/Domain Forwarding
If you want the Zimbra server to relay all mail destined for a particular domain (say, example.com) to another mta (say, other-mta.domain.com), you can forward the domain.
zmprov md example.com zimbraMailCatchAllAddress @example.com md example.com zimbraMailCatchAllForwardingAddress @example.com md example.com zimbraMailTransport smtp:other-mta.domain.com
I think you can also do this as another way to make a sort of local domain alias:
zmprov md example.com zimbraMailCatchAllAddress @example.com md example.com zimbraMailCatchAllForwardingAddress @domain.com md example.com zimbraMailTransport lmtp:zimbra.domain.com
Domain Masquerading
If you want mail from user@domain.com or user@zimbra.domain.com to appear to come from user@example.com, you can set the canonical address for the entire domain.
zmprov md domain.com zimbraMailCatchAllAddress @domain.com zimbraMailCatchAllCanonicalAddress @example.com zmprov md zimbra.domain.com zimbraMailCatchAllAddress @zimbra.domain.com zimbraMailCatchAllCanonicalAddress @example.com