Plus Addressing is a feature that allows a sender to append a tag to the user id of a recipient. This lets the recipient more easily sort the incoming mail using a mail filter.
For example, email@example.com could also be reached using the address firstname.lastname@example.org.
To enable Plus Addressing with Zimbra, use zmprov as follows:
zmprov mcf zimbraMtaRecipientDelimiter +
Note that the delimiter can be a character other than '+'.
To disable Plus Addressing, use zmprov as follows:
zmprov mcf -- -zimbraMtaRecipientDelimiter +
After making changes to enable or disable this feature, you can restart the postfix service :
And check that the postfix configuration has the right value :
postconf recipient_delimiter recipient_delimiter = +
Disable addresses (since 8.5.0)
If you want to disable a specific address, e.g. because it has been targeted by spam, you can enable a postfix recipient and client restriction map.
Create the postfix recipient access file:
Edit the file to include the address:
email@example.com 550 User Unknown
Build the lmdb file:
zmprov mcf +zimbraMtaRestriction "check_recipient_access lmdb:/opt/zimbra/conf/postfix_recipient_access"