Allowing users to specify a forwarding address is a COS enabled feature. You can also manage this feature from individual accounts.
You can add the forwarding address in the account's Forwarding tab and users can enter a forwarding address from their Zimbra Web Client Options Mail tab. The forwarding address is always displayed in the Account Forwarding tab.
As mail comes into an account with forwarding enabled and an address configured, a copy is sent to the forwarding address. If the forwarded message should be deleted, you can set Disable local delivery on the account's Preferences tab. If this feature is enabled in Accounts, users can set Disable local delivery from the ZWC Option Mail tab.
In an account's Forwarding tab, you can specify forwarding addresses that is hidden from the user. When mail is delivered, a copy is forwarded to the address listed. The user does not know that the email was forwarded.
Mail forwarding can be disabled from the COS or the Account. When mail forwarding is disabled, the option to create a forwarding address and to disable local delivery does not appear on the user's Option Mail tab and Mail Filters tab. You must remove the forwarding address that is in the account's Forwarding tab.
If you disable forwarding and a forwarding address is already specified in the account, forwarding will continue.