For "various reasons" I need email@example.com to be delivered to user@domain.
I've tried the alias domain instructions given in the Wiki (ManagingDomains - Zimbra :: Wiki) which works, but means that mail for any user @mailhost.domain will be accepted, then bounced if necessary, which isn't good.
I've also tried adding
masquerade_classes = envelope_sender, header_sender, header_recipient, envelope_recipient
masquerade_domains = mailhost.domain domain
remote_header_rewrite_domain = domain
to the postfix config but this doesn't appear to have any effect.
The other thing I could do is add mailhost.domain as a normal domain and then explicitly create an alias for each user, but I'd like to avoid this.
Does anyone else have any other suggestions?