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NetBSD 6.1.5 - man page for proxymap (netbsd section 8)

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PROXYMAP(8)									      PROXYMAP(8)

NAME
       proxymap - Postfix lookup table proxy server

SYNOPSIS
       proxymap [generic Postfix daemon options]

DESCRIPTION
       The  proxymap(8)  server  provides read-only or read-write table lookup service to Postfix
       processes. These services are implemented with distinct service names: proxymap and proxy-
       write, respectively. The purpose of these services is:

       o      To  overcome  chroot restrictions. For example, a chrooted SMTP server needs access
	      to the system passwd file in order to reject mail for non-existent local addresses,
	      but  it  is not practical to maintain a copy of the passwd file in the chroot jail.
	      The solution:

	      local_recipient_maps =
		  proxy:unix:passwd.byname $alias_maps

       o      To consolidate the number of open lookup tables by sharing  one  open  table  among
	      multiple processes. For example, making mysql connections from every Postfix daemon
	      process results in "too many connections" errors. The solution:

	      virtual_alias_maps =
		  proxy:mysql:/etc/postfix/virtual_alias.cf

	      The total number of connections is limited by the number of  proxymap  server  pro-
	      cesses.

       o      To provide single-updater functionality for lookup tables that do not reliably sup-
	      port multiple writers (i.e. all file-based tables).

       The proxymap(8) server implements the following requests:

       open maptype:mapname flags
	      Open the table with type maptype and name mapname,  as  controlled  by  flags.  The
	      reply  includes  the  maptype  dependent flags (to distinguish a fixed string table
	      from a regular expression table).

       lookup maptype:mapname flags key
	      Look up the data stored under the requested key.	The reply is the request  comple-
	      tion  status  code  and the lookup result value.	The maptype:mapname and flags are
	      the same as with the open request.

       update maptype:mapname flags key value
	      Update the data stored under the requested key.  The reply is the  request  comple-
	      tion  status  code.   The  maptype:mapname  and flags are the same as with the open
	      request.

	      To implement single-updater maps, specify a process limit of  1  in  the	master.cf
	      file entry for the proxywrite service.

	      This request is supported in Postfix 2.5 and later.

       delete maptype:mapname flags key
	      Delete  the  data stored under the requested key.  The reply is the request comple-
	      tion status code.  The maptype:mapname and flags are the	same  as  with	the  open
	      request.

	      This request is supported in Postfix 2.5 and later.

       The  request  completion  status is one of OK, RETRY, NOKEY (lookup failed because the key
       was not found), BAD (malformed request) or DENY (the table is not approved for proxy  read
       or update access).

       There is no close command, nor are tables implicitly closed when a client disconnects. The
       purpose is to share tables among multiple client processes.

SERVER PROCESS MANAGEMENT
       proxymap(8) servers run under control by the Postfix master(8) server.	Each  server  can
       handle  multiple  simultaneous connections.  When all servers are busy while a client con-
       nects, the master(8) creates a new proxymap(8) server process, provided that  the  process
       limit  is not exceeded.	Each server terminates after serving at least $max_use clients or
       after $max_idle seconds of idle time.

SECURITY
       The proxymap(8) server opens only tables that are  approved  via  the  proxy_read_maps  or
       proxy_write_maps  configuration	parameters,  does not talk to users, and can run at fixed
       low privilege, chrooted or not.	However, running the proxymap  server  chrooted  severely
       limits usability, because it can open only chrooted tables.

       The  proxymap(8)  server  is not a trusted daemon process, and must not be used to look up
       sensitive information such as user or group IDs, mailbox file/directory names or  external
       commands.

       In  Postfix version 2.2 and later, the proxymap client recognizes requests to access a ta-
       ble for security-sensitive purposes, and opens the table directly. This	allows	the  same
       main.cf setting to be used by sensitive and non-sensitive processes.

       Postfix-writable  data files should be stored under a dedicated directory that is writable
       only by the Postfix mail system, such as the Postfix-owned data_directory.

       In particular, Postfix-writable files should never exist in root-owned  directories.  That
       would  open  up	a particular type of security hole where ownership of a file or directory
       does not match the provider of its content.

DIAGNOSTICS
       Problems and transactions are logged to syslogd(8).

BUGS
       The proxymap(8) server provides service to multiple clients, and  must  therefore  not  be
       used for tables that have high-latency lookups.

       The  proxymap(8)  read-write  service  does not explicitly close lookup tables (even if it
       did, this could not be relied on, because the process  may  be  terminated  between  table
       updates).  The read-write service should therefore not be used with tables that leave per-
       sistent storage in an inconsistent state between updates (for example, CDB).  Tables  that
       support	"sync  on update" should be safe (for example, Berkeley DB) as should tables that
       are implemented by a real DBMS.

CONFIGURATION PARAMETERS
       On busy mail systems a long time may pass before proxymap(8) relevant changes  to  main.cf
       are picked up. Use the command "postfix reload" to speed up a change.

       The text below provides only a parameter summary. See postconf(5) for more details includ-
       ing examples.

       config_directory (see 'postconf -d' output)
	      The default location of the Postfix main.cf and master.cf configuration files.

       data_directory (see 'postconf -d' output)
	      The directory with Postfix-writable data files (for example: caches,  pseudo-random
	      numbers).

       daemon_timeout (18000s)
	      How  much  time  a Postfix daemon process may take to handle a request before it is
	      terminated by a built-in watchdog timer.

       ipc_timeout (3600s)
	      The time limit for sending or receiving information over an internal  communication
	      channel.

       max_idle (100s)
	      The  maximum amount of time that an idle Postfix daemon process waits for an incom-
	      ing connection before terminating voluntarily.

       max_use (100)
	      The maximal number of incoming connections that a Postfix daemon process will  ser-
	      vice before terminating voluntarily.

       process_id (read-only)
	      The process ID of a Postfix command or daemon process.

       process_name (read-only)
	      The process name of a Postfix command or daemon process.

       proxy_read_maps (see 'postconf -d' output)
	      The  lookup  tables  that the proxymap(8) server is allowed to access for the read-
	      only service.

       Available in Postfix 2.5 and later:

       data_directory (see 'postconf -d' output)
	      The directory with Postfix-writable data files (for example: caches,  pseudo-random
	      numbers).

       proxy_write_maps (see 'postconf -d' output)
	      The  lookup  tables  that the proxymap(8) server is allowed to access for the read-
	      write service.

SEE ALSO
       postconf(5), configuration parameters
       master(5), generic daemon options

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.

HISTORY
       The proxymap service was introduced with Postfix 2.0.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA

										      PROXYMAP(8)
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