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📛 NAME

postalias - Postfix alias database maintenance

🚀 Quick Reference

Use Case	Command	Description
Create alias database	postalias [file_type:]file_name	Build a new alias database from source file
Query a single key	postalias -q key [file_type:]file_name	Look up and print the first value for a key
Delete a key	postalias -d key [file_type:]file_name	Remove one entry per map
List all entries	postalias -s [file_type:]file_name	Dump all key-value pairs in database order
Incremental update	postalias -i [file_type:]file_name	Read entries from stdin, do not truncate database
Force update existing entries	postalias -r [file_type:]file_name	Overwrite existing entries without warning

📋 SYNOPSIS

postalias [-Nfinoprsuvw] [-c config_dir] [-d key] [-q key]
        [file_type:]file_name ...

📝 DESCRIPTION

The postalias(1) command creates or queries one or more Postfix alias databases, or updates an existing one. The input and output file formats are expected to be compatible with Sendmail version 8, and are expected to be suitable for the use as NIS alias maps.

If the result files do not exist they will be created with the same group and other read permissions as their source file.

While a database update is in progress, signal delivery is postponed, and an exclusive, advisory, lock is placed on the entire database, in order to avoid surprises in spectator processes.

The format of Postfix alias input files is described in aliases(5).

By default the lookup key is mapped to lowercase to make the lookups case insensitive; as of Postfix 2.3 this case folding happens only with tables whose lookup keys are fixed-case strings such as btree:, dbm: or hash:. With earlier versions, the lookup key is folded even with tables where a lookup field can match both upper and lower case text, such as regexp: and pcre:. This resulted in loss of information with $number substitutions.

⚙️ Options

• -c config_dir — Read the main.cf configuration file in the named directory instead of the default configuration directory.
• -d key — Search the specified maps for key and remove one entry per map. The exit status is zero when the requested information was found. If a key value of - is specified, the program reads key values from the standard input stream. The exit status is zero when at least one of the requested keys was found.
• -f — Do not fold the lookup key to lower case while creating or querying a table. With Postfix version 2.3 and later, this option has no effect for regular expression tables. There, case folding is controlled by appending a flag to a pattern.
• -i — Incremental mode. Read entries from standard input and do not truncate an existing database. By default, postalias(1) creates a new database from the entries in file_name.
• -N — Include the terminating null character that terminates lookup keys and values. By default, postalias(1) does whatever is the default for the host operating system.
• -n — Don't include the terminating null character that terminates lookup keys and values. By default, postalias(1) does whatever is the default for the host operating system.
• -o — Do not release root privileges when processing a non-root input file. By default, postalias(1) drops root privileges and runs as the source file owner instead.
• -p — Do not inherit the file access permissions from the input file when creating a new file. Instead, create a new file with default access permissions (mode 0644).
• -q key — Search the specified maps for key and write the first value found to the standard output stream. The exit status is zero when the requested information was found. Note: this performs a single query with the key as specified, and does not make iterative queries with substrings of the key as described in the aliases(5) manual page. If a key value of - is specified, the program reads key values from the standard input stream and writes one line of key: value output for each key that was found. The exit status is zero when at least one of the requested keys was found.
• -r — When updating a table, do not complain about attempts to update existing entries, and make those updates anyway.
• -s — Retrieve all database elements, and write one line of key: value output for each element. The elements are printed in database order, which is not necessarily the same as the original input order. This feature is available in Postfix version 2.2 and later, and is not available for all database types.
• -u — Disable UTF-8 support. UTF-8 support is enabled by default when smtputf8_enable = yes. It requires that keys and values are valid UTF-8 strings.
• -v — Enable verbose logging for debugging purposes. Multiple -v options make the software increasingly verbose.
• -w — When updating a table, do not complain about attempts to update existing entries, and ignore those attempts.

📁 Arguments

• file_type — The database type. To find out what types are supported, use the postconf -m command. The postalias(1) command can query any supported file type, but it can create only the following file types:
  • btree — The output is a btree file, named file_name.db. Available on systems with support for db databases.
  • cdb — The output is one file named file_name.cdb. Available on systems with support for cdb databases.
  • dbm — The output consists of two files, named file_name.pag and file_name.dir. Available on systems with support for dbm databases.
  • fail — A table that reliably fails all requests. The lookup table name is used for logging only. This table exists to simplify Postfix error tests.
  • hash — The output is a hashed file, named file_name.db. Available on systems with support for db databases.
  • lmdb — The output is a btree-based file, named file_name.lmdb. lmdb supports concurrent writes and reads from different processes, unlike other supported file-based tables. Available on systems with support for lmdb databases.
  • sdbm — The output consists of two files, named file_name.pag and file_name.dir. Available on systems with support for sdbm databases.
  When no file_type is specified, the software uses the database type specified via the default_database_type configuration parameter. The default value for this parameter depends on the host environment.
• file_name — The name of the alias database source file when creating a database.

🔍 DIAGNOSTICS

Problems are logged to the standard error stream and to syslogd(8) or postlogd(8). No output means that no problems were detected. Duplicate entries are skipped and are flagged with a warning.

postalias(1) terminates with zero exit status in case of success (including successful postalias -q lookup) and terminates with non-zero exit status in case of failure.

🌐 ENVIRONMENT

• MAIL_CONFIG — Directory with Postfix configuration files.
• MAIL_VERBOSE — Enable verbose logging for debugging purposes.

⚙️ CONFIGURATION PARAMETERS

The following main.cf parameters are especially relevant to this program. The text below provides only a parameter summary. See postconf(5) for more details including examples.

• alias_database (see 'postconf -d' output) — The alias databases for local(8) delivery that are updated with newaliases or with sendmail -bi.
• config_directory (see 'postconf -d' output) — The default location of the Postfix main.cf and master.cf configuration files.
• berkeley_db_create_buffer_size (16777216) — The per-table I/O buffer size for programs that create Berkeley DB hash or btree tables.
• berkeley_db_read_buffer_size (131072) — The per-table I/O buffer size for programs that read Berkeley DB hash or btree tables.
• default_database_type (see 'postconf -d' output) — The default database type for use in newaliases(1), postalias(1) and postmap(1) commands.
• import_environment (see 'postconf -d' output) — The list of environment parameters that a privileged Postfix process will import from a non-Postfix parent process, or name=value environment overrides.
• smtputf8_enable (yes) — Enable preliminary SMTPUTF8 support for the protocols described in RFC 6531..6533.
• syslog_facility (mail) — The syslog facility of Postfix logging.
• syslog_name (see 'postconf -d' output) — A prefix that is prepended to the process name in syslog records, so that, for example, "smtpd" becomes "prefix/smtpd".
• Available in Postfix 2.11 and later:
  • lmdb_map_size (16777216) — The initial OpenLDAP LMDB database size limit in bytes.

📜 STANDARDS

RFC 822 (ARPA Internet Text Messages)

📚 SEE ALSO

• aliases(5), format of alias database input file.
• local(8), Postfix local delivery agent.
• postconf(1), supported database types
• postconf(5), configuration parameters
• postmap(1), create/update/query lookup tables
• newaliases(1), Sendmail compatibility interface.
• postlogd(8), Postfix logging
• syslogd(8), system logging

📖 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

📛 NAME 🚀 Quick Reference 📋 SYNOPSIS 📝 DESCRIPTION 🔍 DIAGNOSTICS 🌐 ENVIRONMENT ⚙️ CONFIGURATION PARAMETERS 📜 STANDARDS 📚 SEE ALSO 📖 README FILES 📄 LICENSE 👤 AUTHOR(S)