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

6       transport - Postfix transport table format
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SYNOPSIS

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

16       The   optional  transport(5)  table  specifies  a  mapping  from  email
17       addresses to message delivery  transports  and  next-hop  destinations.
18       Message  delivery  transports  such as local or smtp are defined in the
19       master.cf file, and next-hop destinations are typically hosts or domain
20       names. The table is searched by the trivial-rewrite(8) daemon.
21
22       This  mapping overrides the default transport:nexthop selection that is
23       built into Postfix:
24
25       local_transport (default: local:$myhostname)
26              This is the default for final delivery to  domains  listed  with
27              mydestination,  and  for  [ipaddress]  destinations  that  match
28              $inet_interfaces or $proxy_interfaces. The default nexthop  des‐
29              tination is the MTA hostname.
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31       virtual_transport (default: virtual:)
32              This  is  the  default for final delivery to domains listed with
33              virtual_mailbox_domains. The default nexthop destination is  the
34              recipient domain.
35
36       relay_transport (default: relay:)
37              This  is  the default for remote delivery to domains listed with
38              relay_domains. In order of decreasing  precedence,  the  nexthop
39              destination   is   taken   from  relay_transport,  sender_depen‐
40              dent_relayhost_maps, relayhost, or from the recipient domain.
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42       default_transport (default: smtp:)
43              This is the default for remote delivery to  other  destinations.
44              In  order  of  decreasing precedence, the nexthop destination is
45              taken from  default_transport,  sender_dependent_relayhost_maps,
46              relayhost, or from the recipient domain.
47
48       Normally,  the  transport(5)  table  is  specified  as a text file that
49       serves as input to the postmap(1) command.  The result, an indexed file
50       in  dbm  or  db  format, is used for fast searching by the mail system.
51       Execute the command  "postmap  /etc/postfix/transport"  to  rebuild  an
52       indexed file after changing the corresponding transport table.
53
54       When  the  table  is provided via other means such as NIS, LDAP or SQL,
55       the same lookups are done as for ordinary indexed files.
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57       Alternatively, the table can be provided as  a  regular-expression  map
58       where  patterns  are  given  as  regular expressions, or lookups can be
59       directed to TCP-based server. In those case, the lookups are done in  a
60       slightly  different  way  as  described below under "REGULAR EXPRESSION
61       TABLES" or "TCP-BASED TABLES".
62

CASE FOLDING

64       The search string is folded to lowercase before database lookup. As  of
65       Postfix  2.3,  the search string is not case folded with database types
66       such as regexp: or pcre: whose lookup fields can match both  upper  and
67       lower case.
68

TABLE FORMAT

70       The input format for the postmap(1) command is as follows:
71
72       pattern result
73              When  pattern  matches  the recipient address or domain, use the
74              corresponding result.
75
76       blank lines and comments
77              Empty lines and whitespace-only lines are ignored, as are  lines
78              whose first non-whitespace character is a `#'.
79
80       multi-line text
81              A  logical  line  starts  with  non-whitespace text. A line that
82              starts with whitespace continues a logical line.
83
84       The pattern specifies an email address, a domain name, or a domain name
85       hierarchy, as described in section "TABLE LOOKUP".
86
87       The  result is of the form transport:nexthop and specifies how or where
88       to deliver mail. This is described in section "RESULT FORMAT".
89

TABLE SEARCH ORDER

91       With lookups from indexed files such as DB or DBM,  or  from  networked
92       tables  such  as  NIS,  LDAP or SQL, patterns are tried in the order as
93       listed below:
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95       user+extension@domain transport:nexthop
96              Deliver mail for user+extension@domain through transport to nex‐
97              thop.
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99       user@domain transport:nexthop
100              Deliver mail for user@domain through transport to nexthop.
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102       domain transport:nexthop
103              Deliver mail for domain through transport to nexthop.
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105       .domain transport:nexthop
106              Deliver  mail  for  any subdomain of domain through transport to
107              nexthop. This applies only when the string transport_maps is not
108              listed  in  the  parent_domain_matches_subdomains  configuration
109              setting.  Otherwise, a domain name matches itself and its subdo‐
110              mains.
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112       Note 1: the special pattern * represents any address (i.e. it functions
113       as the wild-card pattern).
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115       Note   2:   the   null   recipient   address   is    looked    up    as
116       $empty_address_recipient@$myhostname (default: mailer-daemon@hostname).
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118       Note  3:  user@domain  or  user+extension@domain lookup is available in
119       Postfix 2.0 and later.
120

RESULT FORMAT

122       The lookup result is of  the  form  transport:nexthop.   The  transport
123       field  specifies  a  mail delivery transport such as smtp or local. The
124       nexthop field specifies where and how to deliver mail.
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126       The transport field specifies the name of  a  mail  delivery  transport
127       (the  first  name  of a mail delivery service entry in the Postfix mas‐
128       ter.cf file).
129
130       The interpretation of the nexthop field is transport dependent. In  the
131       case  of SMTP, specify a service on a non-default port as host:service,
132       and disable MX (mail exchanger) DNS lookups with [host] or [host]:port.
133       The  []  form  is  required when you specify an IP address instead of a
134       hostname.
135
136       A null transport and null nexthop result means "do not change": use the
137       delivery  transport and nexthop information that would be used when the
138       entire transport table did not exist.
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140       A non-null transport field with a null nexthop field resets the nexthop
141       information to the recipient domain.
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143       A  null transport field with non-null nexthop field does not modify the
144       transport information.
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EXAMPLES

147       In order to deliver internal mail directly, while using  a  mail  relay
148       for  all other mail, specify a null entry for internal destinations (do
149       not change the delivery transport or the nexthop information) and spec‐
150       ify a wildcard for all other destinations.
151
152            my.domain    :
153            .my.domain   :
154            *            smtp:outbound-relay.my.domain
155
156       In  order  to send mail for example.com and its subdomains via the uucp
157       transport to the UUCP host named example:
158
159            example.com      uucp:example
160            .example.com     uucp:example
161
162       When no nexthop host name is specified, the destination domain name  is
163       used  instead.  For  example, the following directs mail for user@exam‐
164       ple.com via the slow transport to a  mail  exchanger  for  example.com.
165       The  slow  transport  could  be  configured to run at most one delivery
166       process at a time:
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168            example.com      slow:
169
170       When no transport is specified, Postfix uses the transport that matches
171       the  address domain class (see DESCRIPTION above).  The following sends
172       all mail for example.com  and  its  subdomains  to  host  gateway.exam‐
173       ple.com:
174
175            example.com      :[gateway.example.com]
176            .example.com     :[gateway.example.com]
177
178       In  the  above example, the [] suppress MX lookups.  This prevents mail
179       routing loops when your machine is primary MX host for example.com.
180
181       In the case of delivery via  SMTP,  one  may  specify  hostname:service
182       instead of just a host:
183
184            example.com      smtp:bar.example:2025
185
186       This  directs  mail for user@example.com to host bar.example port 2025.
187       Instead of a numerical port a symbolic name may  be  used.  Specify  []
188       around the hostname if MX lookups must be disabled.
189
190       The error mailer can be used to bounce mail:
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192            .example.com     error:mail for *.example.com is not deliverable
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194       This causes all mail for user@anything.example.com to be bounced.
195

REGULAR EXPRESSION TABLES

197       This  section  describes how the table lookups change when the table is
198       given in the form of regular expressions. For a description of  regular
199       expression lookup table syntax, see regexp_table(5) or pcre_table(5).
200
201       Each  pattern  is  a  regular  expression that is applied to the entire
202       address being looked up. Thus, some.domain.hierarchy is not  looked  up
203       via   its   parent   domains,  nor  is  user+foo@domain  looked  up  as
204       user@domain.
205
206       Patterns are applied in the order as specified in the  table,  until  a
207       pattern is found that matches the search string.
208
209       The trivial-rewrite(8) server disallows regular expression substitution
210       of $1 etc. in regular expression lookup tables, because that could open
211       a security hole (Postfix version 2.3 and later).
212

TCP-BASED TABLES

214       This  section  describes  how the table lookups change when lookups are
215       directed  to  a  TCP-based  server.  For  a  description  of  the   TCP
216       client/server  lookup  protocol, see tcp_table(5).  This feature is not
217       available up to and including Postfix version 2.4.
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219       Each lookup operation uses the entire recipient  address  once.   Thus,
220       some.domain.hierarchy  is  not looked up via its parent domains, nor is
221       user+foo@domain looked up as user@domain.
222
223       Results are the same as with indexed file lookups.
224

CONFIGURATION PARAMETERS

226       The following main.cf parameters are  especially  relevant.   The  text
227       below  provides  only  a  parameter  summary.  See postconf(5) for more
228       details including examples.
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230       empty_address_recipient
231              The address that  is  looked  up  instead  of  the  null  sender
232              address.
233
234       parent_domain_matches_subdomains
235              List  of  Postfix features that use domain.tld patterns to match
236              sub.domain.tld (as opposed to requiring .domain.tld patterns).
237
238       transport_maps
239              List of transport lookup tables.
240

SEE ALSO

242       trivial-rewrite(8), rewrite and resolve addresses
243       postconf(5), configuration parameters
244       postmap(1), Postfix lookup table manager
245

README FILES

247       Use "postconf readme_directory" or "postconf html_directory" to  locate
248       this information.
249       ADDRESS_REWRITING_README, address rewriting guide
250       DATABASE_README, Postfix lookup table overview
251       FILTER_README, external content filter
252

LICENSE

254       The Secure Mailer license must be distributed with this software.
255

AUTHOR(S)

257       Wietse Venema
258       IBM T.J. Watson Research
259       P.O. Box 704
260       Yorktown Heights, NY 10598, USA
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