postfix-master/virtual.5.html

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   7 VIRTUAL(5)                                                          VIRTUAL(5)
   8
   9 <b>NAME</b>
  10        virtual - Postfix virtual alias table format
  11
  12 <b>SYNOPSIS</b>
  13        <b>postmap /etc/postfix/virtual</b>
  14
  15        <b>postmap -q "</b><i>string</i><b>" /etc/postfix/virtual</b>
  16
  17        <b>postmap -q - /etc/postfix/virtual</b> &lt;<i>inputfile</i>
  18
  19 <b>DESCRIPTION</b>
  20        The  optional  <a href="virtual.5.html"><b>virtual</b>(5)</a>  alias  table rewrites recipient
  21        addresses for all local, all virtual, and all remote  mail
  22        destinations.   This  is unlike the <a href="aliases.5.html"><b>aliases</b>(5)</a> table which
  23        is used only for <a href="local.8.html"><b>local</b>(8)</a> delivery.  Virtual  aliasing  is
  24        recursive,  and  is  implemented by the Postfix <a href="cleanup.8.html"><b>cleanup</b>(8)</a>
  25        daemon before mail is queued.
  26
  27        The main applications of virtual aliasing are:
  28
  29        <b>o</b>      To redirect mail for one address  to  one  or  more
  30               addresses.
  31
  32        <b>o</b>      To   implement  virtual  alias  domains  where  all
  33               addresses  are  aliased  to  addresses   in   other
  34               domains.
  35
  36               Virtual  alias  domains are not to be confused with
  37               the <a href="ADDRESS_CLASS_README.html#virtual_mailbox_class">virtual mailbox domains</a>  that  are  implemented
  38               with  the  Postfix  <a href="virtual.8.html"><b>virtual</b>(8)</a> mail delivery agent.
  39               With  virtual  mailbox  domains,   each   recipient
  40               address can have its own mailbox.
  41
  42        Virtual  aliasing  is  applied  only to recipient envelope
  43        addresses, and  does  not  affect  message  headers.   Use
  44        <a href="canonical.5.html"><b>canonical</b>(5)</a>   mapping  to  rewrite  header  and  envelope
  45        addresses in general.
  46
  47        Normally, the <a href="virtual.5.html"><b>virtual</b>(5)</a> alias table  is  specified  as  a
  48        text  file that serves as input to the <a href="postmap.1.html"><b>postmap</b>(1)</a> command.
  49        The result, an indexed file in <b>dbm</b> or <b>db</b> format,  is  used
  50        for fast searching by the mail system. Execute the command
  51        "<b>postmap /etc/postfix/virtual</b>" to rebuild an indexed  file
  52        after changing the corresponding text file.
  53
  54        When  the  table  is provided via other means such as NIS,
  55        LDAP or SQL, the same lookups are  done  as  for  ordinary
  56        indexed files.
  57
  58        Alternatively,  the  table  can  be provided as a regular-
  59        expression map where patterns are given as regular expres-
  60        sions,  or lookups can be directed to TCP-based server. In
  61        those case, the lookups are done in a  slightly  different
  62        way  as  described below under "REGULAR EXPRESSION TABLES"
  63        or "TCP-BASED TABLES".
  64
  65 <b>CASE FOLDING</b>
  66        The search string is folded to lowercase  before  database
  67        lookup.  As  of Postfix 2.3, the search string is not case
  68        folded with database types such as <a href="regexp_table.5.html">regexp</a>: or <a href="pcre_table.5.html">pcre</a>:  whose
  69        lookup fields can match both upper and lower case.
  70
  71 <b>TABLE FORMAT</b>
  72        The input format for the <a href="postmap.1.html"><b>postmap</b>(1)</a> command is as follows:
  73
  74        <i>pattern result</i>
  75               When <i>pattern</i> matches a mail address, replace it  by
  76               the corresponding <i>result</i>.
  77
  78        blank lines and comments
  79               Empty  lines and whitespace-only lines are ignored,
  80               as are lines whose first  non-whitespace  character
  81               is a `#'.
  82
  83        multi-line text
  84               A  logical  line starts with non-whitespace text. A
  85               line that starts with whitespace continues a  logi-
  86               cal line.
  87
  88 <b>TABLE SEARCH ORDER</b>
  89        With lookups from indexed files such as DB or DBM, or from
  90        networked tables such as NIS, LDAP or  SQL,  patterns  are
  91        tried in the order as listed below:
  92
  93        <i>user</i>@<i>domain address, address, ...</i>
  94               Redirect  mail  for  <i>user</i>@<i>domain</i>  to <i>address</i>.  This
  95               form has the highest precedence.
  96
  97        <i>user address, address, ...</i>
  98               Redirect mail for <i>user</i>@<i>site</i> to <i>address</i> when <i>site</i> is
  99               equal  to $<b><a href="postconf.5.html#myorigin">myorigin</a></b>, when <i>site</i> is listed in $<b><a href="postconf.5.html#mydestination">mydes</a>-</b>
 100               <b><a href="postconf.5.html#mydestination">tination</a></b>, or when it is listed in  $<b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b>
 101               or $<b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>.
 102
 103               This  functionality  overlaps with functionality of
 104               the local <i>aliases</i>(5) database.  The  difference  is
 105               that <a href="virtual.5.html"><b>virtual</b>(5)</a> mapping can be applied to non-local
 106               addresses.
 107
 108        @<i>domain address, address, ...</i>
 109               Redirect mail for other users in <i>domain</i> to <i>address</i>.
 110               This form has the lowest precedence.
 111
 112               Note:  @<i>domain</i>  is a wild-card. With this form, the
 113               Postfix SMTP server accepts mail for any  recipient
 114               in  <i>domain</i>,  regardless  of  whether that recipient
 115               exists.  This may turn  your  mail  system  into  a
 116               backscatter  source: Postfix first accepts mail for
 117               non-existent recipients and then  tries  to  return
 118               that  mail  as  "undeliverable" to the often forged
 119               sender address.
 120
 121 <b>RESULT ADDRESS REWRITING</b>
 122        The lookup result is subject to address rewriting:
 123
 124        <b>o</b>      When the result  has  the  form  @<i>otherdomain</i>,  the
 125               result  becomes the same <i>user</i> in <i>otherdomain</i>.  This
 126               works only for the first address in a multi-address
 127               lookup result.
 128
 129        <b>o</b>      When  "<b><a href="postconf.5.html#append_at_myorigin">append_at_myorigin</a>=yes</b>", append "<b>@$<a href="postconf.5.html#myorigin">myorigin</a></b>"
 130               to addresses without "@domain".
 131
 132        <b>o</b>      When "<b><a href="postconf.5.html#append_dot_mydomain">append_dot_mydomain</a>=yes</b>", append "<b>.$<a href="postconf.5.html#mydomain">mydomain</a></b>"
 133               to addresses without ".domain".
 134
 135 <b>ADDRESS EXTENSION</b>
 136        When a mail address localpart contains the optional recip-
 137        ient delimiter (e.g., <i>user+foo</i>@<i>domain</i>), the  lookup  order
 138        becomes: <i>user+foo</i>@<i>domain</i>, <i>user</i>@<i>domain</i>, <i>user+foo</i>, <i>user</i>, and
 139        @<i>domain</i>.
 140
 141        The  <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>   parameter   controls
 142        whether  an  unmatched  address extension (<i>+foo</i>) is propa-
 143        gated to the result of table lookup.
 144
 145 <b>VIRTUAL ALIAS DOMAINS</b>
 146        Besides virtual aliases, the virtual alias table can  also
 147        be used to implement <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domains</a>. With a virtual
 148        alias domain,  all  recipient  addresses  are  aliased  to
 149        addresses in other domains.
 150
 151        Virtual alias domains are not to be confused with the vir-
 152        tual mailbox domains that are implemented with the Postfix
 153        <a href="virtual.8.html"><b>virtual</b>(8)</a>  mail  delivery  agent.  With  virtual  mailbox
 154        domains, each recipient address can have its own  mailbox.
 155
 156        With  a  virtual  alias domain, the virtual domain has its
 157        own user name space. Local  (i.e.  non-virtual)  usernames
 158        are  not visible in a <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a>. In particular,
 159        local <a href="aliases.5.html"><b>aliases</b>(5)</a> and local mailing lists are  not  visible
 160        as <i>localname@virtual-alias.domain</i>.
 161
 162        Support for a <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a> looks like:
 163
 164        /etc/postfix/<a href="postconf.5.html">main.cf</a>:
 165            <a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a> = hash:/etc/postfix/virtual
 166
 167        Note: some systems use <b>dbm</b> databases instead of <b>hash</b>.  See
 168        the output  from  "<b>postconf  -m</b>"  for  available  database
 169        types.
 170
 171        /etc/postfix/virtual:
 172            <i>virtual-alias.domain     anything</i> (right-hand content does not matter)
 173            <i>postmaster@virtual-alias.domain  postmaster</i>
 174            <i>user1@virtual-alias.domain       address1</i>
 175            <i>user2@virtual-alias.domain       address2, address3</i>
 176
 177        The  <i>virtual-alias.domain anything</i> entry is required for a
 178        <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a>. <b>Without this entry, mail is rejected</b>
 179        <b>with  "relay  access  denied", or bounces with "mail loops</b>
 180        <b>back to myself".</b>
 181
 182        Do not specify <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domain</a> names in  the  <a href="postconf.5.html"><b>main.cf</b></a>
 183        <b><a href="postconf.5.html#mydestination">mydestination</a></b> or <b><a href="postconf.5.html#relay_domains">relay_domains</a></b> configuration parameters.
 184
 185        With  a  virtual  alias  domain,  the  Postfix SMTP server
 186        accepts  mail  for  <i>known-user@virtual-alias.domain</i>,   and
 187        rejects   mail  for  <i>unknown-user</i>@<i>virtual-alias.domain</i>  as
 188        undeliverable.
 189
 190        Instead of specifying the virtual alias  domain  name  via
 191        the  <b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a></b> table, you may also specify it via
 192        the <a href="postconf.5.html"><b>main.cf</a> <a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a></b> configuration parameter.
 193        This  latter parameter uses the same syntax as the <a href="postconf.5.html"><b>main.cf</b></a>
 194        <b><a href="postconf.5.html#mydestination">mydestination</a></b> configuration parameter.
 195
 196 <b>REGULAR EXPRESSION TABLES</b>
 197        This section describes how the table lookups  change  when
 198        the table is given in the form of regular expressions. For
 199        a description of regular expression lookup  table  syntax,
 200        see <a href="regexp_table.5.html"><b>regexp_table</b>(5)</a> or <a href="pcre_table.5.html"><b>pcre_table</b>(5)</a>.
 201
 202        Each  pattern  is  a regular expression that is applied to
 203        the entire address being looked up. Thus, <i>user@domain</i> mail
 204        addresses  are  not  broken up into their <i>user</i> and <i>@domain</i>
 205        constituent parts, nor is <i>user+foo</i> broken up into <i>user</i> and
 206        <i>foo</i>.
 207
 208        Patterns  are applied in the order as specified in the ta-
 209        ble, until a pattern is  found  that  matches  the  search
 210        string.
 211
 212        Results  are  the  same as with indexed file lookups, with
 213        the additional feature that parenthesized substrings  from
 214        the pattern can be interpolated as <b>$1</b>, <b>$2</b> and so on.
 215
 216 <b>TCP-BASED TABLES</b>
 217        This  section  describes how the table lookups change when
 218        lookups are directed to a TCP-based server. For a descrip-
 219        tion of the TCP client/server lookup protocol, see <a href="tcp_table.5.html"><b>tcp_ta-</b></a>
 220        <a href="tcp_table.5.html"><b>ble</b>(5)</a>.  This feature is not available up to and including
 221        Postfix version 2.4.
 222
 223        Each lookup operation uses the entire address once.  Thus,
 224        <i>user@domain</i> mail addresses are not broken  up  into  their
 225        <i>user</i> and <i>@domain</i> constituent parts, nor is <i>user+foo</i> broken
 226        up into <i>user</i> and <i>foo</i>.
 227
 228        Results are the same as with indexed file lookups.
 229
 230 <b>BUGS</b>
 231        The table format does not understand quoting  conventions.
 232
 233 <b>CONFIGURATION PARAMETERS</b>
 234        The  following  <a href="postconf.5.html"><b>main.cf</b></a> parameters are especially relevant
 235        to this topic. See the Postfix  <a href="postconf.5.html"><b>main.cf</b></a>  file  for  syntax
 236        details  and  for default values. Use the "<b>postfix reload</b>"
 237        command after a configuration change.
 238
 239        <b><a href="postconf.5.html#virtual_alias_maps">virtual_alias_maps</a></b>
 240               List of virtual aliasing tables.
 241
 242        <b><a href="postconf.5.html#virtual_alias_domains">virtual_alias_domains</a></b>
 243               List of <a href="ADDRESS_CLASS_README.html#virtual_alias_class">virtual alias domains</a>. This uses  the  same
 244               syntax as the <b><a href="postconf.5.html#mydestination">mydestination</a></b> parameter.
 245
 246        <b><a href="postconf.5.html#propagate_unmatched_extensions">propagate_unmatched_extensions</a></b>
 247               A  list  of  address rewriting or forwarding mecha-
 248               nisms that propagate an address extension from  the
 249               original  address  to  the result.  Specify zero or
 250               more  of  <b>canonical</b>,   <b>virtual</b>,   <b>alias</b>,   <b>forward</b>,
 251               <b>include</b>, or <b>generic</b>.
 252
 253        Other parameters of interest:
 254
 255        <b><a href="postconf.5.html#inet_interfaces">inet_interfaces</a></b>
 256               The  network  interface  addresses that this system
 257               receives mail on.  You need to stop and start Post-
 258               fix when this parameter changes.
 259
 260        <b><a href="postconf.5.html#mydestination">mydestination</a></b>
 261               List  of  domains  that  this mail system considers
 262               local.
 263
 264        <b><a href="postconf.5.html#myorigin">myorigin</a></b>
 265               The domain that is appended  to  any  address  that
 266               does not have a domain.
 267
 268        <b><a href="postconf.5.html#owner_request_special">owner_request_special</a></b>
 269               Give special treatment to <b>owner-</b><i>xxx</i> and <i>xxx</i><b>-request</b>
 270               addresses.
 271
 272        <b><a href="postconf.5.html#proxy_interfaces">proxy_interfaces</a></b>
 273               Other interfaces that this machine receives mail on
 274               by way of a proxy agent or network address transla-
 275               tor.
 276
 277 <b>SEE ALSO</b>
 278        <a href="cleanup.8.html">cleanup(8)</a>, canonicalize and enqueue mail
 279        <a href="postmap.1.html">postmap(1)</a>, Postfix lookup table manager
 280        <a href="postconf.5.html">postconf(5)</a>, configuration parameters
 281        <a href="canonical.5.html">canonical(5)</a>, canonical address mapping
 282
 283 <b>README FILES</b>
 284        <a href="ADDRESS_REWRITING_README.html">ADDRESS_REWRITING_README</a>, address rewriting guide
 285        <a href="DATABASE_README.html">DATABASE_README</a>, Postfix lookup table overview
 286        <a href="VIRTUAL_README.html">VIRTUAL_README</a>, domain hosting guide
 287
 288 <b>LICENSE</b>
 289        The  Secure  Mailer  license must be distributed with this
 290        software.
 291
 292 <b>AUTHOR(S)</b>
 293        Wietse Venema
 294        IBM T.J. Watson Research
 295        P.O. Box 704
 296        Yorktown Heights, NY 10598, USA
 297
 298                                                                     VIRTUAL(5)
 299 </pre> </body> </html>