1GENERIC(5)                    File Formats Manual                   GENERIC(5)
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NAME

6       generic - Postfix generic table format
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SYNOPSIS

9       postmap /etc/postfix/generic
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11       postmap -q "string" /etc/postfix/generic
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13       postmap -q - /etc/postfix/generic <inputfile
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DESCRIPTION

16       The optional generic(5) table specifies an address mapping that applies
17       when mail is delivered. This is the opposite of  canonical(5)  mapping,
18       which applies when mail is received.
19
20       Typically, one would use the generic(5) table on a system that does not
21       have a valid Internet domain name and that uses something like localdo‐
22       main.local  instead.   The generic(5) table is then used by the smtp(8)
23       client to transform local  mail  addresses  into  valid  Internet  mail
24       addresses  when mail has to be sent across the Internet.  See the EXAM‐
25       PLE section at the end of this document.
26
27       The generic(5) mapping affects  both  message  header  addresses  (i.e.
28       addresses  that  appear inside messages) and message envelope addresses
29       (for example, the addresses that are used in SMTP protocol commands).
30
31       Normally, the generic(5) table is specified as a text file that  serves
32       as input to the postmap(1) command.  The result, an indexed file in dbm
33       or db format, is used for fast searching by the  mail  system.  Execute
34       the  command  "postmap /etc/postfix/generic" to rebuild an indexed file
35       after changing the corresponding text file.
36
37       When the table is provided via other means such as NIS,  LDAP  or  SQL,
38       the same lookups are done as for ordinary indexed files.
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40       Alternatively,  the  table  can be provided as a regular-expression map
41       where patterns are given as regular  expressions,  or  lookups  can  be
42       directed  to TCP-based server. In those case, the lookups are done in a
43       slightly different way as described  below  under  "REGULAR  EXPRESSION
44       TABLES" or "TCP-BASED TABLES".
45

CASE FOLDING

47       The  search string is folded to lowercase before database lookup. As of
48       Postfix 2.3, the search string is not case folded with  database  types
49       such  as  regexp: or pcre: whose lookup fields can match both upper and
50       lower case.
51

TABLE FORMAT

53       The input format for the postmap(1) command is as follows:
54
55       pattern result
56              When pattern matches a mail address, replace it  by  the  corre‐
57              sponding result.
58
59       blank lines and comments
60              Empty  lines and whitespace-only lines are ignored, as are lines
61              whose first non-whitespace character is a `#'.
62
63       multi-line text
64              A logical line starts with  non-whitespace  text.  A  line  that
65              starts with whitespace continues a logical line.
66

TABLE SEARCH ORDER

68       With  lookups  from  indexed files such as DB or DBM, or from networked
69       tables such as NIS, LDAP or SQL,  each  user@domain  query  produces  a
70       sequence of query patterns as described below.
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72       Each query pattern is sent to each specified lookup table before trying
73       the next query pattern, until a match is found.
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75       user@domain address
76              Replace user@domain by address. This form has the highest prece‐
77              dence.
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79       user address
80              Replace  user@site  by  address when site is equal to $myorigin,
81              when site is listed in $mydestination, or when it is  listed  in
82              $inet_interfaces or $proxy_interfaces.
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84       @domain address
85              Replace other addresses in domain by address.  This form has the
86              lowest precedence.
87

RESULT ADDRESS REWRITING

89       The lookup result is subject to address rewriting:
90
91       ·      When the result has the form @otherdomain,  the  result  becomes
92              the same user in otherdomain.
93
94       ·      When  "append_at_myorigin=yes", append "@$myorigin" to addresses
95              without "@domain".
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97       ·      When "append_dot_mydomain=yes", append ".$mydomain" to addresses
98              without ".domain".
99

ADDRESS EXTENSION

101       When a mail address localpart contains the optional recipient delimiter
102       (e.g., user+foo@domain), the  lookup  order  becomes:  user+foo@domain,
103       user@domain, user+foo, user, and @domain.
104
105       The   propagate_unmatched_extensions   parameter  controls  whether  an
106       unmatched address extension (+foo) is propagated to the result of table
107       lookup.
108

REGULAR EXPRESSION TABLES

110       This  section  describes how the table lookups change when the table is
111       given in the form of regular expressions. For a description of  regular
112       expression lookup table syntax, see regexp_table(5) or pcre_table(5).
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114       Each  pattern  is  a  regular  expression that is applied to the entire
115       address being looked up. Thus, user@domain mail addresses are not  bro‐
116       ken  up  into their user and @domain constituent parts, nor is user+foo
117       broken up into user and foo.
118
119       Patterns are applied in the order as specified in the  table,  until  a
120       pattern is found that matches the search string.
121
122       Results  are the same as with indexed file lookups, with the additional
123       feature that parenthesized substrings from the pattern can be  interpo‐
124       lated as $1, $2 and so on.
125

TCP-BASED TABLES

127       This  section  describes  how the table lookups change when lookups are
128       directed  to  a  TCP-based  server.  For  a  description  of  the   TCP
129       client/server  lookup  protocol, see tcp_table(5).  This feature is not
130       available up to and including Postfix version 2.4.
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132       Each lookup operation uses the entire address once.  Thus,  user@domain
133       mail  addresses  are  not  broken  up  into their user and @domain con‐
134       stituent parts, nor is user+foo broken up into user and foo.
135
136       Results are the same as with indexed file lookups.
137

EXAMPLE

139       The following shows a generic mapping with an indexed file.  When  mail
140       is  sent to a remote host via SMTP, this replaces his@localdomain.local
141       by his ISP mail address, replaces her@localdomain.local by her ISP mail
142       address, and replaces other local addresses by his ISP account, with an
143       address extension of +local (this example assumes that the ISP supports
144       "+" style address extensions).
145
146       /etc/postfix/main.cf:
147           smtp_generic_maps = hash:/etc/postfix/generic
148
149       /etc/postfix/generic:
150           his@localdomain.local   hisaccount@hisisp.example
151           her@localdomain.local   heraccount@herisp.example
152           @localdomain.local      hisaccount+local@hisisp.example
153
154       Execute  the  command "postmap /etc/postfix/generic" whenever the table
155       is changed.  Instead of hash, some systems use dbm database  files.  To
156       find  out  what  tables  your system supports use the command "postconf
157       -m".
158

BUGS

160       The table format does not understand quoting conventions.
161

CONFIGURATION PARAMETERS

163       The following main.cf parameters are  especially  relevant.   The  text
164       below  provides  only  a  parameter  summary.  See postconf(5) for more
165       details including examples.
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167       smtp_generic_maps
168              Address mapping lookup table for envelope and header sender  and
169              recipient addresses while delivering mail via SMTP.
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171       propagate_unmatched_extensions
172              A list of address rewriting or forwarding mechanisms that propa‐
173              gate an address extension  from  the  original  address  to  the
174              result.  Specify zero or more of canonical, virtual, alias, for‐
175              ward, include, or generic.
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177       Other parameters of interest:
178
179       inet_interfaces
180              The network interface addresses that this system  receives  mail
181              on.   You  need  to  stop  and start Postfix when this parameter
182              changes.
183
184       proxy_interfaces
185              Other interfaces that this machine receives mail on by way of  a
186              proxy agent or network address translator.
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188       mydestination
189              List of domains that this mail system considers local.
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191       myorigin
192              The domain that is appended to locally-posted mail.
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194       owner_request_special
195              Give special treatment to owner-xxx and xxx-request addresses.
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SEE ALSO

198       postmap(1), Postfix lookup table manager
199       postconf(5), configuration parameters
200       smtp(8), Postfix SMTP client
201

README FILES

203       Use  "postconf readme_directory" or "postconf html_directory" to locate
204       this information.
205       ADDRESS_REWRITING_README, address rewriting guide
206       DATABASE_README, Postfix lookup table overview
207       STANDARD_CONFIGURATION_README, configuration examples
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LICENSE

210       The Secure Mailer license must be distributed with this software.
211

HISTORY

213       A genericstable feature appears in the Sendmail MTA.
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215       This feature is available in Postfix 2.2 and later.
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AUTHOR(S)

218       Wietse Venema
219       IBM T.J. Watson Research
220       P.O. Box 704
221       Yorktown Heights, NY 10598, USA
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223       Wietse Venema
224       Google, Inc.
225       111 8th Avenue
226       New York, NY 10011, USA
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