# man > postconf(1) > **TLDR:** Postfix configuration utility. > - Specify the directory of the `main.cf` configuration file instead of the default configuration directory: `postconf -c {{path/to/configuration_directory}}` - Edit the `main.cf` configuration file and update parameter settings with the "name=value" pairs: `postconf -e` - Print the default parameter settings of the `main.cf` instead of the actual settings: `postconf -d` - Display parameters only from the specified class: `postconf -C {{builtin|service|user|all}}` - List available SASL plug-in types for the Postfix SMTP server. The plug-in type is selected with the `smtpd_sasl_type` configuration parameter by specifying `cyrus` or `dovecot` as the name: `postconf -a` - List the names of all supported lookup table types. Lookup tables are specified as `type:name` in configuration files where the type can be `btree`, `cdb`, `hash`, `mysql`, etc: `postconf -m` *Source: tldr-pages* --- [_POSTCONF_(1)](https://www.chedong.com/phpMan.php/man/POSTCONF/1/markdown) General Commands Manual [_POSTCONF_(1)](https://www.chedong.com/phpMan.php/man/POSTCONF/1/markdown) ## NAME postconf - Postfix configuration utility ## SYNOPSIS ### Managing main.cf: **postconf **[**-dfhHnopvx**] [**-c _**config_dir_] [**-C _**class,..._] [_parameter_ _..._] **postconf **[**-epv**] [**-c _**config_dir_] _parameter_**=_**value_ _..._ **postconf -# **[**-pv**] [**-c _**config_dir_] _parameter_ _..._ **postconf -X **[**-pv**] [**-c _**config_dir_] _parameter_ _..._ ### Managing master.cf service entries: **postconf -M **[**-fovx**] [**-c _**config_dir_] [_service_[**/_**type_] _..._] **postconf -M **[**-ev**] [**-c _**config_dir_] _service_**/_**type_**=_**value_ _..._ **postconf -M# **[**-v**] [**-c _**config_dir_] _service_**/_**type_ _..._ **postconf -MX **[**-v**] [**-c _**config_dir_] _service_**/_**type_ _..._ ### Managing master.cf service fields: **postconf -F **[**-fhHovx**] [**-c _**config_dir_] [_service_[**/_**type_[**/_**field_]] _..._] **postconf -F **[**-ev**] [**-c _**config_dir_] _service_**/_**type_**/_**field_**=_**value_ _..._ ### Managing master.cf service parameters: **postconf -P **[**-fhHovx**] [**-c _**config_dir_] [_service_[**/_**type_[**/_**parameter_]] _..._] **postconf -P **[**-ev**] [**-c _**config_dir_] _service_**/_**type_**/_**parameter_**=_**value_ _..._ **postconf -PX **[**-v**] [**-c _**config_dir_] _service_**/_**type_**/_**parameter_ _..._ ### Managing bounce message templates: **postconf -b **[**-v**] [**-c _**config_dir_] [_template_file_] **postconf -t **[**-v**] [**-c _**config_dir_] [_template_file_] ### Managing TLS features: **postconf -T _**mode_ [**-v**] [**-c _**config_dir_] ### Managing other configuration: **postconf -a**|**-A**|**-l**|**-m **[**-v**] [**-c _**config_dir_] ## DESCRIPTION By default, the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command displays the values of **main.cf **configuration parameters, and warns about possible mis-typed parameter names (Postfix 2.9 and later). The command can also change **main.cf **configuration parameter values, or display other configuration informa‐ tion about the Postfix mail system. Options: ### -a selected with the **smtpd_sasl_type **configuration parameter by specifying one of the names listed below. **cyrus **This server plug-in is available when Postfix is built with Cyrus SASL support. **dovecot** This server plug-in uses the Dovecot authentication server, and is available when Postfix is built with any form of SASL support. This feature is available with Postfix 2.3 and later. ### -A is selected with the **smtp_sasl_type **or **lmtp_sasl_type **configuration parameters by specifying one of the names listed below. **cyrus **This client plug-in is available when Postfix is built with Cyrus SASL support. This feature is available with Postfix 2.3 and later. ### -b Display the message text that appears at the beginning of delivery status notification (DSN) messages, expanding $**name **expressions with actual values as described in [**bounce**(5)](https://www.chedong.com/phpMan.php/man/bounce/5/markdown). To override the **bounce_template_file **parameter setting, specify a template file name at the end of the "**postconf -b**" command line. Specify an empty file name to display built-in templates (in shell language: ""). This feature is available with Postfix 2.3 and later. ### -c _ The **main.cf **configuration file is in the named directory instead of the default con‐ figuration directory. ### -C _ When displaying **main.cf **parameters, select only parameters from the specified class(es): **builtin** Parameters with built-in names. **service** Parameters with service-defined names (the first field of a **master.cf **entry plus a Postfix-defined suffix). **user **Parameters with user-defined names. **all **All the above classes. The default is as if "**-C all**" is specified. This feature is available with Postfix 2.9 and later. ### -d -df fold long lines for human readability (Postfix 2.9 and later). ### -e "_name=value_" pairs on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. With **-M**, edit the **master.cf **configuration file, and replace one or more service en‐ tries with new values as specified with "_service/type=value_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) com‐ mand line. With **-F**, edit the **master.cf **configuration file, and replace one or more service fields with new values as specified with "_service/type/field=value_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) com‐ mand line. Currently, the "command" field contains the command name and command argu‐ ments. This may change in the near future, so that the "command" field contains only the command name, and a new "arguments" pseudofield contains the command arguments. With **-P**, edit the **master.cf **configuration file, and add or update one or more service parameter settings (-o parameter=value settings) with new values as specified with "_service/type/parameter=value_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. In all cases the file is copied to a temporary file then renamed into place. Specify quotes to protect special characters and whitespace on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. The **-e **option is no longer needed with Postfix version 2.8 and later, as it is assumed whenever a value is specified (empty or non-empty). ### -f man readability. This feature is available with Postfix 2.9 and later. ### -F matted as "_service/type/field=value_", one per line. Specify **-Ff **to fold long lines. Specify one or more "_service/type/field_" instances on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line to limit the output to fields of interest. Trailing parameter name or service type fields that are omitted will be handled as "*" wildcard fields. This feature is available with Postfix 2.11 and later. ### -h the value. ### -H name. This feature is available with Postfix 3.1 and later. ### -l ing methods: **flock **A kernel-based advisory locking method for local files only. This locking method is available on systems with a BSD compatible library. **fcntl **A kernel-based advisory locking method for local and remote files. **dotlock** An application-level locking method. An application locks a file named _filename_ by creating a file named _filename_**.lock**. The application is expected to remove its own lock file, as well as stale lock files that were left behind after ab‐ normal program termination. ### -m lookup tables are specified as _type_**:_**name_, where _type_ is one of the types listed below. The table _name_ syntax depends on the lookup table type as described in the DATA‐ BASE_README document. **btree **A sorted, balanced tree structure. Available on systems with support for Berkeley DB databases. **cdb **A read-optimized structure with no support for incremental updates. Available on systems with support for CDB databases. This feature is available with Postfix 2.2 and later. **cidr **A table that associates values with Classless Inter-Domain Routing (CIDR) pat‐ terns. This is described in [**cidr_table**(5)](https://www.chedong.com/phpMan.php/man/cidrtable/5/markdown). This feature is available with Postfix 2.2 and later. **dbm **An indexed file type based on hashing. Available on systems with support for DBM databases. **environ** The UNIX process environment array. The lookup key is the environment variable name; the table name is ignored. Originally implemented for testing, someone may find this useful someday. **fail **A table that reliably fails all requests. The lookup table name is used for logging. This table exists to simplify Postfix error tests. This feature is available with Postfix 2.9 and later. **hash **An indexed file type based on hashing. Available on systems with support for Berkeley DB databases. **inline **(read-only) A non-shared, in-memory lookup table. Example: "**inline:{ _**key_**=_**value_**, { _**key_ **=** _text_ _with_ _whitespace_ _or_ _comma_ **}}**". Key-value pairs are separated by whitespace or comma; with a key-value pair inside "**{}**", whitespace is ignored after the opening "**{**", around the "**=**" between key and value, and before the closing "**}**". Inline tables eliminate the need to create a database file for just a few fixed elements. See also the _static:_ map type. This feature is available with Postfix 3.0 and later. **internal** A non-shared, in-memory hash table. Its content are lost when a process termi‐ nates. **lmdb **OpenLDAP LMDB database (a memory-mapped, persistent file). Available on sys‐ tems with support for LMDB databases. This is described in [**lmdb_table**(5)](https://www.chedong.com/phpMan.php/man/lmdbtable/5/markdown). This feature is available with Postfix 2.11 and later. **ldap **(read-only) LDAP database client. This is described in [**ldap_table**(5)](https://www.chedong.com/phpMan.php/man/ldaptable/5/markdown). **memcache** Memcache database client. This is described in [**memcache_table**(5)](https://www.chedong.com/phpMan.php/man/memcachetable/5/markdown). This feature is available with Postfix 2.9 and later. **mysql **(read-only) MySQL database client. Available on systems with support for MySQL databases. This is described in [**mysql_table**(5)](https://www.chedong.com/phpMan.php/man/mysqltable/5/markdown). **pcre **(read-only) A lookup table based on Perl Compatible Regular Expressions. The file format is described in [**pcre_table**(5)](https://www.chedong.com/phpMan.php/man/pcretable/5/markdown). **pgsql **(read-only) PostgreSQL database client. This is described in [**pgsql_table**(5)](https://www.chedong.com/phpMan.php/man/pgsqltable/5/markdown). This feature is available with Postfix 2.1 and later. **pipemap **(read-only) A lookup table that constructs a pipeline of tables. Example: "**pipemap:{_**type_1:name_1,_ _...,_ _type_n:name_n_**}**". Each "pipemap:" query is given to the first table. Each lookup result becomes the query for the next table in the pipeline, and the last table produces the final result. When any table lookup produces no result, the pipeline produces no result. The first and last characters of the "pipemap:" table name must be "**{**" and "**}**". Within these, in‐ dividual maps are separated with comma or whitespace. This feature is available with Postfix 3.0 and later. **proxy **Postfix [**proxymap**(8)](https://www.chedong.com/phpMan.php/man/proxymap/8/markdown) client for shared access to Postfix databases. The table name syntax is _type_**:_**name_. This feature is available with Postfix 2.0 and later. **randmap **(read-only) An in-memory table that performs random selection. Example: "**randmap:{_**result_1,_ _...,_ _result_n_**}**". Each table query returns a random choice from the specified results. The first and last characters of the "randmap:" table name must be "**{**" and "**}**". Within these, individual results are separated with comma or white‐ space. To give a specific result more weight, specify it multiple times. This feature is available with Postfix 3.0 and later. **regexp **(read-only) A lookup table based on regular expressions. The file format is described in [**regexp_table**(5)](https://www.chedong.com/phpMan.php/man/regexptable/5/markdown). **sdbm **An indexed file type based on hashing. Available on systems with support for SDBM databases. This feature is available with Postfix 2.2 and later. **socketmap **(read-only) Sendmail-style socketmap client. The table name is **inet**:_host_:_port_:_name_ for a TCP/IP server, or **unix**:_pathname_:_name_ for a UNIX-domain server. This is de‐ scribed in [**socketmap_table**(5)](https://www.chedong.com/phpMan.php/man/socketmaptable/5/markdown). This feature is available with Postfix 2.10 and later. **sqlite **(read-only) SQLite database. This is described in [**sqlite_table**(5)](https://www.chedong.com/phpMan.php/man/sqlitetable/5/markdown). This feature is available with Postfix 2.8 and later. **static **(read-only) A table that always returns its name as lookup result. For example, **static:foo‐** **bar **always returns the string **foobar **as lookup result. Specify "**static:{ _**text_ _with_ _whitespace_ **}**" when the result contains whitespace; this form ignores whitespace after the opening "**{**" and before the closing "**}**". See also the _in‐_ _line:_ map. The form "**static:{_**text_**} **is available with Postfix 3.0 and later. **tcp **(read-only) TCP/IP client. The protocol is described in [**tcp_table**(5)](https://www.chedong.com/phpMan.php/man/tcptable/5/markdown). **texthash **(read-only) Produces similar results as hash: files, except that you don't need to run the [**postmap**(1)](https://www.chedong.com/phpMan.php/man/postmap/1/markdown) command before you can use the file, and that it does not detect changes after the file is read. This feature is available with Postfix 2.8 and later. **unionmap **(read-only) A table that sends each query to multiple lookup tables and that concatenates all found results, separated by comma. The table name syntax is the same as for **pipemap**. This feature is available with Postfix 3.0 and later. **unix **(read-only) A limited view of the UNIX authentication database. The following tables are implemented: **unix:passwd.byname** The table is the UNIX password database. The key is a login name. The result is a password file entry in [**passwd**(5)](https://www.chedong.com/phpMan.php/man/passwd/5/markdown) format. **unix:group.byname** The table is the UNIX group database. The key is a group name. The re‐ sult is a group file entry in [**group**(5)](https://www.chedong.com/phpMan.php/man/group/5/markdown) format. Other table types may exist depending on how Postfix was built. ### -M -Mf long lines for human readability. Specify zero or more arguments, each with a _service-name_ or _service-name/service-type_ pair, where _service-name_ is the first field of a master.cf entry and _service-type_ is one of (**inet**, **unix**, **fifo**, or **pass**). If _service-name_ or _service-name/service-type_ is specified, only the matching master.cf entries will be output. For example, "**postconf -Mf smtp**" will output all services named "smtp", and "**postconf -Mf smtp/inet**" will output only the smtp service that lis‐ tens on the network. Trailing service type fields that are omitted will be handled as "*" wildcard fields. This feature is available with Postfix 2.9 and later. The syntax was changed from "_name.type_" to "_name/type_", and "*" wildcard support was added with Postfix 2.11. ### -n Specify **-nf **to fold long lines for human readability (Postfix 2.9 and later). To show settings that differ from built-in defaults only, use the following bash syntax: LANG=C comm -23 <(postconf -n) <(postconf -d) Replace "-23" with "-12" to show settings that duplicate built-in defaults. ### -o _ Override **main.cf **parameter settings. This lets you see the effect changing a parame‐ ter would have when it is used in other configuration parameters, e.g.: postconf -x -o stress=yes This feature is available with Postfix 2.10 and later. ### -p This feature is available with Postfix 2.11 and later. ### -P ters), formatted as "_service/type/parameter=value_", one per line. Specify **-Pf **to fold long lines. Specify one or more "_service/type/parameter_" instances on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line to limit the output to parameters of interest. Trailing parameter name or service type fields that are omitted will be handled as "*" wildcard fields. This feature is available with Postfix 2.11 and later. ### -t Display the templates for text that appears at the beginning of delivery status noti‐ fication (DSN) messages, without expanding $**name **expressions. To override the **bounce_template_file **parameter setting, specify a template file name at the end of the "**postconf -t**" command line. Specify an empty file name to display built-in templates (in shell language: ""). This feature is available with Postfix 2.3 and later. ### -T _ If Postfix is compiled without TLS support, the **-T **option produces no output. Other‐ wise, if an invalid _mode_ is specified, the **-T **option reports an error and exits with a non-zero status code. The valid modes are: **compile-version** Output the OpenSSL version that Postfix was compiled with (i.e. the OpenSSL version in a header file). The output format is the same as with the command "**openssl version**". **run-version** Output the OpenSSL version that Postfix is linked with at runtime (i.e. the OpenSSL version in a shared library). **public-key-algorithms** Output the lower-case names of the supported public-key algorithms, one per-line. This feature is available with Postfix 3.1 and later. ### -v -v increasingly verbose. ### -x This feature is available with Postfix 2.10 and later. ### -X [**conf**(1)](https://www.chedong.com/phpMan.php/man/conf/1/markdown) command line. Specify a list of parameter names, not "_name=value_" pairs. With **-M**, edit the **master.cf **configuration file, and remove one or more service entries as specified with "_service/type_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. With **-P**, edit the **master.cf **configuration file, and remove one or more service parame‐ ter settings (-o parameter=value settings) as specified with "_service/type/parameter_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. In all cases the file is copied to a temporary file then renamed into place. Specify quotes to protect special characters on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. There is no [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command to perform the reverse operation. This feature is available with Postfix 2.10 and later. Support for -M and -P was added with Postfix 2.11. **-# **Edit the **main.cf **configuration file, and comment out the parameters named on the **post‐** [**conf**(1)](https://www.chedong.com/phpMan.php/man/conf/1/markdown) command line, so that those parameters revert to their default values. Spec‐ ify a list of parameter names, not "_name=value_" pairs. With **-M**, edit the **master.cf **configuration file, and comment out one or more service entries as specified with "_service/type_" on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. In all cases the file is copied to a temporary file then renamed into place. Specify quotes to protect special characters on the [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command line. There is no [**postconf**(1)](https://www.chedong.com/phpMan.php/man/postconf/1/markdown) command to perform the reverse operation. This feature is available with Postfix 2.6 and later. Support for -M was added with Postfix 2.11. ## DIAGNOSTICS Problems are reported to the standard error stream. ## ENVIRONMENT **MAIL_CONFIG** Directory with Postfix configuration files. ## CONFIGURATION PARAMETERS The following **main.cf **parameters are especially relevant to this program. The text below provides only a parameter summary. See [**postconf**(5)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown) for more details including examples. ### config_directory (see 'postconf -d' output) The default location of the Postfix main.cf and master.cf configuration files. ### bounce_template_file (empty) Pathname of a configuration file with bounce message templates. ## FILES /etc/postfix/main.cf, Postfix configuration parameters /etc/postfix/master.cf, Postfix master daemon configuration ## SEE ALSO [bounce(5)](https://www.chedong.com/phpMan.php/man/bounce/5/markdown), bounce template file format [master(5)](https://www.chedong.com/phpMan.php/man/master/5/markdown), master.cf configuration file syntax [postconf(5)](https://www.chedong.com/phpMan.php/man/postconf/5/markdown), main.cf configuration file syntax ## README FILES Use "**postconf readme_directory**" or "**postconf html_directory**" to locate this information. DATABASE_README, Postfix lookup table overview ## LICENSE The Secure Mailer license must be distributed with this software. **AUTHOR(S)** Wietse Venema IBM T.J. Watson Research P.O. Box 704 Yorktown Heights, NY 10598, USA Wietse Venema Google, Inc. 111 8th Avenue New York, NY 10011, USA [_POSTCONF_(1)](https://www.chedong.com/phpMan.php/man/POSTCONF/1/markdown)