1PROXYMAP(8) System Manager's Manual PROXYMAP(8)
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6 proxymap - Postfix lookup table proxy server
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9 proxymap [generic Postfix daemon options]
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12 The proxymap(8) server provides read-only table lookup service to Post‐
13 fix processes. The purpose of the service is:
14 · To overcome chroot restrictions. For example, a chrooted SMTP
16 server needs access to the system passwd file in order to reject
17 mail for non-existent local addresses, but it is not practical
18 to maintain a copy of the passwd file in the chroot jail. The
19 solution:
20 local_recipient_maps =
22 proxy:unix:passwd.byname $alias_maps
23 · To consolidate the number of open lookup tables by sharing one
25 open table among multiple processes. For example, making mysql
26 connections from every Postfix daemon process results in "too
27 many connections" errors. The solution:
28 virtual_alias_maps =
30 proxy:mysql:/etc/postfix/virtual_alias.cf
31 The total number of connections is limited by the number of
33 proxymap server processes.
34 The proxymap(8) server implements the following requests:
36 open maptype:mapname flags
38 Open the table with type maptype and name mapname, as controlled
39 by flags. The reply includes the maptype dependent flags (to
40 distinguish a fixed string table from a regular expression ta‐
41 ble).
42 lookup maptype:mapname flags key
44 Look up the data stored under the requested key. The reply is
45 the request completion status code (below) and the lookup result
46 value. The maptype:mapname and flags are the same as with the
47 open request.
48 There is no close command, nor are tables implicitly closed when a
50 client disconnects. The purpose is to share tables among multiple
51 client processes.
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54 proxymap(8) servers run under control by the Postfix master(8) server.
55 Each server can handle multiple simultaneous connections. When all
56 servers are busy while a client connects, the master(8) creates a new
57 proxymap(8) server process, provided that the process limit is not
58 exceeded. Each server terminates after serving at least $max_use
59 clients or after $max_idle seconds of idle time.
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62 The proxymap(8) server opens only tables that are approved via the
63 proxy_read_maps configuration parameter, does not talk to users, and
64 can run at fixed low privilege, chrooted or not. However, running the
65 proxymap server chrooted severely limits usability, because it can open
66 only chrooted tables.
67 The proxymap(8) server is not a trusted daemon process, and must not be
69 used to look up sensitive information such as user or group IDs, mail‐
70 box file/directory names or external commands.
71 In Postfix version 2.2 and later, the proxymap client recognizes
73 requests to access a table for security-sensitive purposes, and opens
74 the table directly. This allows the same main.cf setting to be used by
75 sensitive and non-sensitive processes.
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78 Problems and transactions are logged to syslogd(8).
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81 The proxymap(8) server provides service to multiple clients, and must
82 therefore not be used for tables that have high-latency lookups.
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85 On busy mail systems a long time may pass before proxymap(8) relevant
86 changes to main.cf are picked up. Use the command "postfix reload" to
87 speed up a change.
88 The text below provides only a parameter summary. See postconf(5) for
90 more details including examples.
91 config_directory (see 'postconf -d' output)
93 The default location of the Postfix main.cf and master.cf con‐
94 figuration files.
95 daemon_timeout (18000s)
97 How much time a Postfix daemon process may take to handle a
98 request before it is terminated by a built-in watchdog timer.
99 ipc_timeout (3600s)
101 The time limit for sending or receiving information over an
102 internal communication channel.
103 max_idle (100s)
105 The maximum amount of time that an idle Postfix daemon process
106 waits for an incoming connection before terminating voluntarily.
107 max_use (100)
109 The maximal number of incoming connections that a Postfix daemon
110 process will service before terminating voluntarily.
111 process_id (read-only)
113 The process ID of a Postfix command or daemon process.
114 process_name (read-only)
116 The process name of a Postfix command or daemon process.
117 proxy_read_maps (see 'postconf -d' output)
119 The lookup tables that the proxymap(8) server is allowed to
120 access.
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123 postconf(5), configuration parameters
124 master(5), generic daemon options
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127 Use "postconf readme_directory" or "postconf html_directory" to locate
128 this information.
129 DATABASE_README, Postfix lookup table overview
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132 The Secure Mailer license must be distributed with this software.
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135 The proxymap service was introduced with Postfix 2.0.
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138 Wietse Venema
139 IBM T.J. Watson Research
140 P.O. Box 704
141 Yorktown Heights, NY 10598, USA
142 PROXYMAP(8)