Mail to external users and same mail domain

UCS - Univention Corporate Server
,
#1

Hi@all,

we use UCS/Kolab as our mail system. Our mail domain is:
company.com
We have three external users whose may address is in the same domain:

user1@company.com
user2@company.com
user2@company.com

These do not access the UCS/Kopano but fetch/transmit their mails directly from/via ISP (Strato) with Thunderbird. This all works as well.

But if we want to send a mail to these people from here internally via the Kopano server, this does not work because Postfix does not know what is logical.

Under Kolab I had always edited the line “/etc/postfix/main.cf”:

transport_maps = hash:/etc/postfix/transport, hash:/etc/postfix/external_user

and then created the file “/etc/postfix/externe_user”:

user1@company.com smtp:smtp.strato.com
user2@company.com smtp:smtp.strato.com
user3@company.com smtp:smtp.strato.com

and afterwards:

postmap /etc/postfix/external_user
service postfix restart

When I try to send mail to user1@company.com from within the company I get a message in the logfile:

Aug 04 10:11:56 saturn postfix/smtpd[15623]: connect from localhost[127.0.0.1]
Aug 04 10:11:56 saturn postfix/smtpd[15623]: NOQUEUE: reject: RCPT from localhost[127.0.0.1]: 550 5.1.1 <user1@company.com>: Recipient address rejected: User unknown in virtual mailbox table; from=<andreas@company.com> to=<user1@company.com> proto=ESMTP helo=<saturn.intern.lan>
Aug 04 10:11:56 saturn kopano-spooler[15616]: RCPT line gave SMTP error 550 5.1.1 <user1@company.com>: Recipient address rejected: User unknown in virtual mailbox table. (no retry)
Aug 04 10:11:56 saturn postfix/smtpd[15623]: disconnect from localhost[127.0.0.1] ehlo=1 mail=1 rcpt=0/1 data=0/1 quit=1 commands=3/5
Aug 04 10:11:56 saturn kopano-spooler[15616]: SMTP: Error while executing command 'DATA'. Response: 554 5.5.1 Error: no valid recipients
Aug 04 10:11:56 saturn kopano-spooler[15616]: E-mail for user "Andreas.Stedry" could not be sent: cancel message (40580). Notifying user.

what have I forgotten?

with best
sven

#2

Please check, whether the line

transport_maps = hash:/etc/postfix/transport, hash:/etc/postfix/external_user

still exists in main.cf. You should add “, hash:/etc/postfix/external_user” in Univention registry to prevent from deletion.

If you also speak German, please find this thread - maybe it moght help you:

#3

To add to the above afair you still would need objects in the ldap tree for user1@company.com, …

As Postfix first tries to resolve the user from ldap before the transport maps come into play.

#4

Okay, it’s working.

As fbartels wrote, you have to create the users in LDAP with their mail address (option Kopano-User = None).

Then for each user:

ucr set mail/maps/transport/USER1='user1@company.com smtp:[smtp.strato.de]'

with best
sven

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