other versions
- wheezy 2.9.6-2
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- jessie 2.11.3-1+deb8u2
- testing 3.1.4-7
- unstable 3.1.4-7
- experimental 3.2.0-1
PROXYMAP(8postfix) | PROXYMAP(8postfix) |
NAME¶
proxymap - Postfix lookup table proxy serverSYNOPSIS¶
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 proxywrite, respectively. The purpose of these services is:
- •
- 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
- •
- 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
- •
- To provide single-updater functionality for lookup tables that do not reliably support multiple writers (i.e. all file-based tables).
- 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 completion 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 completion status code. The maptype:mapname and
flags are the same as with the open request.
- delete maptype:mapname flags key
- Delete the data stored under the requested key. The reply
is the request completion status code. The maptype:mapname and
flags are the same as with the open request.
- sequence maptype:mapname flags function
- Iterate over the specified database. The function is
one of DICT_SEQ_FUN_FIRST or DICT_SEQ_FUN_NEXT. The reply is the request
completion status code and a lookup key and result value, if found.
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 connects, 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.
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.
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.
- 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 incoming connection before terminating voluntarily.
- max_use (100)
- The maximal number of incoming connections that a Postfix daemon process will service 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.
- 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