MYSQL_TABLE(5) File Formats Manual MYSQL_TABLE(5)
NAME
mysql_table - Postfix MySQL/MariaDB client configuration
SYNOPSIS
postmap -q "string" mysql:/etc/postfix/filename
postmap -q - mysql:/etc/postfix/filename <inputfile
DESCRIPTION
The Postfix mail system uses optional tables for address rewriting or
mail routing. These tables are usually in lmdb:, cdb:, hash:, or dbm:
format.
Alternatively, lookup tables can be specified as MySQL databases. To
find out what types of lookup tables your Postfix system supports use
the "postconf -m" command.
In order to use MySQL lookups, define a MySQL source as a lookup table
in main.cf, for example:
alias_maps = mysql:/etc/postfix/mysql-aliases.cf
The file /etc/postfix/mysql-aliases.cf has the same format as the Post‐
fix main.cf file, and can specify the parameters described below.
Even though the component name is 'mysql' in Postfix, MariaDB/MySQL
client and servers can be used interchangeably as the functionality
Postfix relies on is available in both. However, their code bases may
still diverge in the future.
LIST MEMBERSHIP
When using SQL to store lists such as $mynetworks, $mydestination, $re‐
lay_domains, $local_recipient_maps, etc., it is important to understand
that the table must store each list member as a separate key. The table
lookup verifies the *existence* of the key. See "Postfix lists versus
tables" in the DATABASE_README document for a discussion.
Do NOT create tables that return the full list of domains in $mydesti‐
nation or $relay_domains etc., or IP addresses in $mynetworks.
DO create tables with each matching item as a key and with an arbitrary
value. With SQL databases it is not uncommon to return the key itself
or a constant value.
MYSQL PARAMETERS
hosts The hosts that Postfix will try to connect to and query from.
Specify unix: for UNIX domain sockets, inet: for TCP connections
(default). Examples:
hosts = inet:host1.some.domain inet:host2.some.domain:port
hosts = host1.some.domain host2.some.domain:port
hosts = unix:/file/name
The hosts are tried in random order, with all connections over
UNIX domain sockets being tried before those over TCP. The con‐
nections are automatically closed after being idle for about 1
minute, and are re-opened as necessary. Postfix versions 2.0 and
earlier do not randomize the host order.
NOTE: if you specify localhost as a hostname (even if you prefix
it with inet:), MySQL will connect to the default UNIX domain
socket. In order to instruct MySQL to connect to localhost over
TCP you have to specify
hosts = 127.0.0.1
NOTE: if the hosts setting specifies only one server, this
client assumes that the target is a load balancer and will re‐
connect immediately after a single failure. With Postfix ver‐
sions 3.9 and earlier, specify the same server twice.
user
password
The user name and password to log into the mysql server. Exam‐
ple:
user = someone
password = some_password
dbname The database name on the servers. Example:
dbname = customer_database
charset (default: utf8mb4)
The default MySQL client character set; this also implies the
collation order.
This parameter is available with Postfix 3.9 and later. With
earlier Postfix versions, the default was chosen by the MySQL
implementation (utf8mb4 as of MySQL 8.0, latin1 historically).
idle_interval (default: 60)
The number of seconds after which an idle database connection
will be closed.
This feature is available in Postfix 3.9 and later.
retry_interval (default: 60)
The number of seconds that a database connection will be skipped
after an error.
NOTE: if the hosts setting specifies only one server, this
client assumes that the target is a load balancer and will re‐
connect immediately after a single failure. With Postfix ver‐
sions 3.9 and earlier, specify the same server twice.
This feature is available in Postfix 3.9 and later.
query The SQL query template used to search the database, where %s is
a substitute for the address Postfix is trying to resolve, e.g.
query = SELECT replacement FROM aliases WHERE mailbox = '%s'
By default, every query must return a result set (instead of
storing its results in a table); with "require_result_set = no"
(Postfix 3.2 and later), the absence of a result set is treated
as "not found".
This parameter supports the following '%' expansions:
%% This is replaced by a literal '%' character.
%s This is replaced by the input key. SQL quoting is used
to make sure that the input key does not add unexpected
metacharacters.
%u When the input key is an address of the form user@domain,
%u is replaced by the SQL quoted local part of the ad‐
dress. Otherwise, %u is replaced by the entire search
string. If the localpart is empty, the query is sup‐
pressed and returns no results.
%d When the input key is an address of the form user@domain,
%d is replaced by the SQL quoted domain part of the ad‐
dress. Otherwise, the query is suppressed and returns no
results.
%[SUD] The upper-case equivalents of the above expansions behave
in the query parameter identically to their lower-case
counter-parts. With the result_format parameter (see be‐
low), they expand the input key rather than the result
value.
%[1-9] The patterns %1, %2, ... %9 are replaced by the corre‐
sponding most significant component of the input key's
domain. If the input key is user@mail.example.com, then
%1 is com, %2 is example and %3 is mail. If the input key
is unqualified or does not have enough domain components
to satisfy all the specified patterns, the query is sup‐
pressed and returns no results.
The domain parameter described below limits the input keys to
addresses in matching domains. When the domain parameter is
non-empty, SQL queries for unqualified addresses or addresses in
non-matching domains are suppressed and return no results.
This parameter is available with Postfix 2.2. In prior releases
the SQL query was built from the separate parameters: se‐
lect_field, table, where_field and additional_conditions. The
mapping from the old parameters to the equivalent query is:
SELECT [select_field]
FROM [table]
WHERE [where_field] = '%s'
[additional_conditions]
The '%s' in the WHERE clause expands to the escaped search
string. With Postfix 2.2 these legacy parameters are used if
the query parameter is not specified.
NOTE: DO NOT put quotes around the query parameter.
result_format (default: %s)
Format template applied to result attributes. Most commonly used
to append (or prepend) text to the result. This parameter sup‐
ports the following '%' expansions:
%% This is replaced by a literal '%' character.
%s This is replaced by the value of the result attribute.
When result is empty it is skipped.
%u When the result attribute value is an address of the form
user@domain, %u is replaced by the local part of the ad‐
dress. When the result has an empty localpart it is
skipped.
%d When a result attribute value is an address of the form
user@domain, %d is replaced by the domain part of the at‐
tribute value. When the result is unqualified it is
skipped.
%[SUD1-9]
The upper-case and decimal digit expansions interpolate
the parts of the input key rather than the result. Their
behavior is identical to that described with query, and
in fact because the input key is known in advance,
queries whose key does not contain all the information
specified in the result template are suppressed and re‐
turn no results.
For example, using "result_format = smtp:[%s]" allows one to use
a mailHost attribute as the basis of a transport(5) table. After
applying the result format, multiple values are concatenated as
comma separated strings. The expansion_limit and parameter ex‐
plained below allows one to restrict the number of values in the
result, which is especially useful for maps that must return at
most one value.
The default value %s specifies that each result value should be
used as is.
This parameter is available with Postfix 2.2 and later.
NOTE: DO NOT put quotes around the result format!
domain (default: no domain list)
This is a list of domain names, paths to files, or "type:table"
databases. When specified, only fully qualified search keys with
a *non-empty* localpart and a matching domain are eligible for
lookup: 'user' lookups, bare domain lookups and "@domain"
lookups are not performed. This can significantly reduce the
query load on the MySQL server.
domain = postfix.org, hash:/etc/postfix/searchdomains
It is best not to use SQL to store the domains eligible for SQL
lookups.
This parameter is available with Postfix 2.2 and later.
NOTE: DO NOT define this parameter for local(8) aliases, because
the input keys are always unqualified.
expansion_limit (default: 0)
A limit on the total number of result elements returned (as a
comma separated list) by a lookup against the map. A setting of
zero disables the limit. Lookups fail with a temporary error if
the limit is exceeded. Setting the limit to 1 ensures that
lookups do not return multiple values.
option_file
Read options from the given file instead of the default my.cnf
location. This reads options from the [client] option group, op‐
tionally followed by options from the group given with op‐
tion_group.
This parameter is available with Postfix 2.11 and later.
option_group (default: Postfix >=3.2: client, <= 3.1: empty)
Read options from the given group of the mysql options file, af‐
ter reading options from the [client] group.
Postfix 3.2 and later read [client] option group settings by de‐
fault. To disable this specify no option_file and specify "op‐
tion_group =" (i.e. an empty value).
Postfix 3.1 and earlier don't read [client] option group set‐
tings unless a non-empty option_file or option_group value are
specified. To enable this, specify, for example, "option_group =
client".
This parameter is available with Postfix 2.11 and later.
require_result_set (default: yes)
If "yes", require that every query returns a result set. If
"no", treat the absence of a result set as "not found".
This parameter is available with Postfix 3.2 and later.
TLS-RELATED SETTINGS
See https://dev.mysql.com/doc/c-api/en/mysql-options.html or
https://mariadb.com/kb/en/mysql_optionsv/ for details of the underlying
MYSQL_OPT_SSL_* features.
tls_cert_file
File containing client's X509 certificate.
This parameter is available with Postfix 2.11 and later.
tls_key_file
File containing the private key corresponding to tls_cert_file.
This parameter is available with Postfix 2.11 and later.
tls_CAfile
File containing X509 certificates for all of the Certification
Authorities the client will recognize. Takes precedence over
tls_CApath.
This parameter is available with Postfix 2.11 and later.
tls_CApath
Directory containing X509 Certification Authority certificates
in separate individual files.
This parameter is available with Postfix 2.11 and later.
tls_ciphers
The list of permissible ciphers for SSL encryption.
This parameter is available with Postfix 2.11 and later.
tls_verify_cert (default: no)
Verify that the server's name matches the common name in the
certificate.
This parameter is available with Postfix 2.11 and later.
USING MYSQL STORED PROCEDURES
Postfix 3.2 and later support calling a stored procedure instead of us‐
ing a SELECT statement in the query, e.g.
query = CALL lookup('%s')
The previously described '%' expansions can be used in the parameter(s)
to the stored procedure.
By default, every stored procedure call must return a result set, i.e.
every code path must execute a SELECT statement that returns a result
set (instead of storing its results in a table). With "require_re‐
sult_set = no", the absence of a result set is treated as "not found".
A stored procedure must not return multiple result sets. That is,
there must be no code path that executes multiple SELECT statements
that return a result (instead of storing their results in a table).
The following is an example of a stored procedure returning a single
result set:
CREATE [DEFINER=`user`@`host`] PROCEDURE
`lookup`(IN `param` VARCHAR(255))
READS SQL DATA
SQL SECURITY INVOKER
BEGIN
select goto from alias where address=param;
END
OBSOLETE MAIN.CF PARAMETERS
For compatibility with other Postfix lookup tables, MySQL parameters
can also be defined in main.cf. In order to do that, specify as MySQL
source a name that doesn't begin with a slash or a dot. The MySQL pa‐
rameters will then be accessible as the name you've given the source in
its definition, an underscore, and the name of the parameter. For ex‐
ample, if the map is specified as "mysql:mysqlname", the parameter
"hosts" would be defined in main.cf as "mysqlname_hosts".
Note: with this form, the passwords for the MySQL sources are written
in main.cf, which is normally world-readable. Support for this form
will be removed in a future Postfix version.
OBSOLETE QUERY INTERFACE
This section describes an interface that is deprecated as of Postfix
2.2. It is replaced by the more general query interface described
above. If the query parameter is defined, the legacy parameters de‐
scribed here ignored. Please migrate to the new interface as the
legacy interface may be removed in a future release.
The following parameters can be used to fill in a SELECT template
statement of the form:
SELECT [select_field]
FROM [table]
WHERE [where_field] = '%s'
[additional_conditions]
The specifier %s is replaced by the search string, and is escaped so if
it contains single quotes or other odd characters, it will not cause a
parse error, or worse, a security problem.
select_field
The SQL "select" parameter. Example:
select_field = forw_addr
table The SQL "select .. from" table name. Example:
table = mxaliases
where_field
The SQL "select .. where" parameter. Example:
where_field = alias
additional_conditions
Additional conditions to the SQL query. Example:
additional_conditions = AND status = 'paid'
SEE ALSO
postmap(1), Postfix lookup table maintenance
postconf(5), configuration parameters
ldap_table(5), LDAP lookup tables
pgsql_table(5), PostgreSQL lookup tables
sqlite_table(5), SQLite lookup tables
README FILES
DATABASE_README, Postfix lookup table overview
MYSQL_README, Postfix MYSQL client guide
LICENSE
The Secure Mailer license must be distributed with this software.
HISTORY
MySQL support was introduced with Postfix version 1.0.
AUTHOR(S)
Original implementation by:
Scott Cotton, Joshua Marcus
IC Group, Inc.
Further enhancements by:
Liviu Daia
Institute of Mathematics of the Romanian Academy
P.O. BOX 1-764
RO-014700 Bucharest, ROMANIA
Stored-procedure support by John Fawcett.
Wietse Venema
Google, Inc.
111 8th Avenue
New York, NY 10011, USA
MYSQL_TABLE(5)