this is handled in a couple of different ways

please note this is only for virtual users and assumes you are running postfix/dovecot

through postfix (first)

see main.cf :

# SOFT BOUNCE # # The soft_bounce parameter provides a limited safety net for # testing. When soft_bounce is enabled, mail will remain queued that # would otherwise bounce. This parameter disables locally-generated # bounces, and prevents the SMTP server from rejecting mail permanently # (by changing 5xx replies into 4xx replies). However, soft_bounce # is no cure for address rewriting mistakes or mail routing mistakes. #

soft_bounce = yes

the above option in postfix will continually try to deliver to the end user, if the user does not exist it will continue trying without any bounceback to the sender.

this was built into postfix mainly for mail migrations between servers where the dovecot, cyrus server upgrades etc came into play

but should work for your situation.

next on the dovecot side (user database queries)

# cat dovecot-pgsql.conf driver = pgsql connect = host=localhost port=5433 dbname=scom_billing user=pgsql password=Scom411400 default_pass_scheme = PLAIN

password_query = SELECT username as user, password FROM email_users WHERE username = '%u' and password <> 'alias' and status = True and destination = '%u'

user_query = SELECT home, uid, gid FROM email_users WHERE username = '%u' and password <> 'alias' and status = True and destination = '%u'

#iterate_query = SELECT user, password FROM email_users WHERE username = '%u' and password <> 'alias' and status = True and destination = '%u'

iterate_query = SELECT "username" as user, domain FROM email_users WHERE status = True and alias_flag = False

this file reflects how to query the database tables etc

note the status=true above etc, i use this to specify if the account is active and ok or not

if this flag is set to false, dovecot will consider this user non active and not allow delivery locally.

mainly used for billing but will sufice

also note i use an alias flag (from the cyrus days) to forward emails off to another actual active account

i am still streamlining that internally but thought i should explain why it is there

please note iterate_query is used for the replication users (doveadm user '*') query - not needed if you dont run replication but wont hurt anything if it is there.

Happy Wednesday !!! Thanks - paul

Paul Kudla

Scom.ca Internet Services http://www.scom.ca 004-1009 Byron Street South Whitby, Ontario - Canada L1N 4S3

Toronto 416.642.7266 Main 1.866.411.7266 Fax 1.888.892.7266

On 4/20/2022 8:39 AM, Marc wrote:

Is it possible to block incoming messages from being delivered to a specific user in such a way that the MTA will try again later. I do not want these message to bounce. (eg while doing some manual maintenance on the user)?