[mysqld]
set-variable = max_connections=1024

Transcript of session follows.

 Out: 220 poseidon.mydomain.tld ESMTP Postfix (Ubuntu)
 In:  EHLO j121po145.domain.tld
 Out: 250-poseidon.mydomain.tld
 Out: 250-PIPELINING
 Out: 250-SIZE 15728640
 Out: 250-ETRN
 Out: 250-STARTTLS
 Out: 250-AUTH PLAIN LOGIN
 Out: 250-AUTH=PLAIN LOGIN
 Out: 250-ENHANCEDSTATUSCODES
 Out: 250-8BITMIME
 Out: 250 DSN
 In:  MAIL FROM:<testfahrer@senderdomain.tld> BODY=8BITMIME
     ENVID=15__1_1501309757223_702_1309757401
 Out: 250 2.1.0 Ok
 In:  RCPT TO:<myuser@mydomain.tld> NOTIFY=FAILURE
 Out: 451 4.3.0 <testfahrer@senderdomain.tld>: Temporary lookup failure
 In:  DATA
 Out: 554 5.5.1 Error: no valid recipients
 In:  QUIT
 Out: 221 2.0.0 Bye


For other details, see the local mail logfile

Jul  4 22:10:36 poseidon postfix/smtpd[14957]: connect from j121po145.domain.tld[nnn.nnn.nnn.nnn]
Jul  4 22:10:36 poseidon postfix/trivial-rewrite[14922]: warning: transport_maps lookup failure
Jul  4 22:10:36 poseidon postfix/smtpd[14957]: NOQUEUE: reject: RCPT from j121po145.domain.tld[nnn.nnn.nnn.nnn]: 451 4.3.0 <testfahrer@senderdomain.tld>: Temporary lookup failure; from=<testfahrer@senderdomain.tld> to=<myuser@mydomain.tld> proto=ESMTP helo=<j121po145.domain.tld>
Jul  4 22:10:36 poseidon postfix/cleanup[14958]: 41E43252E04: message-id=<20110704201036.41E43252E04@poseidon.mydomain.tld>
Jul  4 22:10:36 poseidon postfix/qmgr[1513]: 41E43252E04: from=<double-bounce@poseidon.mydomain.tld>, size=1187, nrcpt=1 (queue active)
Jul  4 22:10:36 poseidon postfix/smtpd[14957]: disconnect from j121po145.domain.tld[nnn.nnn.nnn.nnn]

Transcript of session follows.

 Out: 220 poseidon.mydomain.tld ESMTP Postfix (Ubuntu)
 In:  EHLO j121po155.domain.tld
 Out: 250-poseidon.mydomain.tld
 Out: 250-PIPELINING
 Out: 250-SIZE 15728640
 Out: 250-ETRN
 Out: 250-STARTTLS
 Out: 250-AUTH PLAIN LOGIN
 Out: 250-AUTH=PLAIN LOGIN
 Out: 250-ENHANCEDSTATUSCODES
 Out: 250-8BITMIME
 Out: 250 DSN
 In:  MAIL FROM:<??hr_geld@senderdomain.tld> BODY=8BITMIME
     ENVID=15__1_1511309431064_883_1309431281
 Out: 250 2.1.0 Ok
 In:  RCPT TO:<myuser@mydomain.tld> NOTIFY=FAILURE
 Out: 451 4.3.0 <  hr_geld@senderdomain.tld>: Temporary lookup failure
 In:  DATA
 Out: 554 5.5.1 Error: no valid recipients
 In:  QUIT
 Out: 221 2.0.0 Bye


For other details, see the local mail logfile

Jul  4 22:09:58 poseidon postfix/smtpd[14957]: connect from j121po155.domain.tld[nnn.nnn.nnn.nnn]
Jul  4 22:09:58 poseidon postfix/proxymap[14923]: warning: mysql query failed: Illegal mix of collations (ascii_general_ci,IMPLICIT) and (latin1_swedish_ci,COERCIBLE) for operation '='
Jul  4 22:09:58 poseidon postfix/trivial-rewrite[14922]: warning: transport_maps lookup failure
Jul  4 22:09:58 poseidon postfix/trivial-rewrite[14922]: warning: transport_maps lookup failure
Jul  4 22:09:58 poseidon postfix/smtpd[14957]: NOQUEUE: reject: RCPT from j121po155.domain.tld[nnn.nnn.nnn.nnn]: 451 4.3.0 <  hr_geld@senderdomain.tld>: Temporary lookup failure; from=<??hr_geld@senderdomain.tld> to=<myuser@mydomain.tld> proto=ESMTP helo=<j121po155.domain.tld>
Jul  4 22:09:58 poseidon postfix/cleanup[14958]: 86471252E02: message-id=<20110704200958.86471252E02@poseidon.mydomain.tld>
Jul  4 22:09:58 poseidon postfix/qmgr[1513]: 86471252E02: from=<double-bounce@poseidon.mydomain.tld>, size=1183, nrcpt=1 (queue active)
Jul  4 22:09:58 poseidon postfix/trivial-rewrite[14922]: warning: transport_maps lookup failure
Jul  4 22:09:58 poseidon postfix/smtpd[14957]: disconnect from j121po155.domain.tld[nnn.nnn.nnn.nnn]

query       = SELECT transport FROM domain WHERE domain='%s' AND active=1

query       = SELECT mailbox.transport FROM mailbox,domain WHERE mailbox.username='%s' AND mailbox.domain='%d' AND mailbox.domain=domain.domain AND mailbox.transport<>'' AND mailbox.active=1 AND mailbox.enabledeliver=1 AND domain.backupmx=0 AND domain.active=1

#  mysql -uroot -p
Enter password:
Welcome to the MySQL monitor.  Commands end with ; or \g.
Your MySQL connection id is 21094
Server version: 5.1.49-1ubuntu8.1 (Ubuntu)

Copyright (c) 2000, 2010, Oracle and/or its affiliates. All rights reserved.
This software comes with ABSOLUTELY NO WARRANTY. This is free software,
and you are welcome to modify and redistribute it under the GPL v2 license

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

mysql> USE vmail;
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed

mysql> DESC mailbox;
+--------------------------+-----------------+------+-----+---------------------+-------+
| Field                    | Type            | Null | Key | Default             | Extra |
+--------------------------+-----------------+------+-----+---------------------+-------+
| username                 | varchar(255)    | NO   | PRI | NULL                |       |
| password                 | varchar(255)    | NO   |     |                     |       |
| name                     | varchar(255)    | NO   |     |                     |       |
| storagebasedirectory     | varchar(255)    | NO   |     | /var/vmail          |       |
| storagenode              | varchar(255)    | NO   |     | vmail1              |       |
| maildir                  | varchar(255)    | NO   |     |                     |       |
| quota                    | bigint(20)      | NO   |     | 0                   |       |
| bytes                    | bigint(20)      | NO   |     | 0                   |       |
| messages                 | bigint(20)      | NO   |     | 0                   |       |
| domain                   | varchar(255)    | NO   | MUL |                     |       |
| transport                | varchar(255)    | NO   |     |                     |       |
| department               | varchar(255)    | NO   | MUL |                     |       |
| rank                     | varchar(255)    | NO   |     | normal              |       |
| employeeid               | varchar(255)    | YES  | MUL |                     |       |
| enablesmtp               | tinyint(1)      | NO   | MUL | 1                   |       |
| enablesmtpsecured        | tinyint(1)      | NO   | MUL | 1                   |       |
| enablepop3               | tinyint(1)      | NO   | MUL | 1                   |       |
| enablepop3secured        | tinyint(1)      | NO   | MUL | 1                   |       |
| enableimap               | tinyint(1)      | NO   | MUL | 1                   |       |
| enableimapsecured        | tinyint(1)      | NO   | MUL | 1                   |       |
| enabledeliver            | tinyint(1)      | NO   | MUL | 1                   |       |
| enablemanagesieve        | tinyint(1)      | NO   | MUL | 1                   |       |
| enablemanagesievesecured | tinyint(1)      | NO   | MUL | 1                   |       |
| enablesieve              | tinyint(1)      | NO   | MUL | 1                   |       |
| enablesievesecured       | tinyint(1)      | NO   | MUL | 1                   |       |
| enableinternal           | tinyint(1)      | NO   | MUL | 1                   |       |
| lastlogindate            | datetime        | NO   |     | 0000-00-00 00:00:00 |       |
| lastloginipv4            | int(4) unsigned | NO   |     | 0                   |       |
| lastloginprotocol        | char(255)       | NO   |     |                     |       |
| disclaimer               | text            | NO   |     | NULL                |       |
| passwordlastchange       | datetime        | NO   | MUL | 0000-00-00 00:00:00 |       |
| created                  | datetime        | NO   |     | 0000-00-00 00:00:00 |       |
| modified                 | datetime        | NO   |     | 0000-00-00 00:00:00 |       |
| expired                  | datetime        | NO   | MUL | 9999-12-31 00:00:00 |       |
| active                   | tinyint(1)      | NO   | MUL | 1                   |       |
| local_part               | varchar(255)    | NO   |     |                     |       |
+--------------------------+-----------------+------+-----+---------------------+-------+
36 rows in set (0.01 sec)

mysql> DESC domain;
+-----------------------+--------------+------+-----+---------------------+-------+
| Field                 | Type         | Null | Key | Default             | Extra |
+-----------------------+--------------+------+-----+---------------------+-------+
| domain                | varchar(255) | NO   | PRI |                     |       |
| description           | text         | NO   |     | NULL                |       |
| disclaimer            | text         | NO   |     | NULL                |       |
| aliases               | int(10)      | NO   |     | 0                   |       |
| mailboxes             | int(10)      | NO   |     | 0                   |       |
| maxquota              | bigint(20)   | NO   |     | 0                   |       |
| quota                 | bigint(20)   | NO   |     | 0                   |       |
| transport             | varchar(255) | NO   |     | dovecot             |       |
| backupmx              | tinyint(1)   | NO   | MUL | 0                   |       |
| defaultuserquota      | bigint(20)   | NO   |     | 1024                |       |
| defaultuseraliases    | text         | NO   |     | NULL                |       |
| defaultpasswordscheme | varchar(10)  | NO   |     |                     |       |
| minpasswordlength     | int(10)      | NO   |     | 0                   |       |
| maxpasswordlength     | int(10)      | NO   |     | 0                   |       |
| created               | datetime     | NO   |     | 0000-00-00 00:00:00 |       |
| modified              | datetime     | NO   |     | 0000-00-00 00:00:00 |       |
| expired               | datetime     | NO   | MUL | 9999-12-31 00:00:00 |       |
| active                | tinyint(1)   | NO   | MUL | 1                   |       |
+-----------------------+--------------+------+-----+---------------------+-------+
18 rows in set (0.00 sec)