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PPoossttffiixx AAddddrreessss RReewwrriittiinngg
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-------------------------------------------------------------------------------
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PPoossttffiixx aaddddrreessss rreewwrriittiinngg ppuurrppoossee
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Address rewriting is at the heart of the Postfix mail system. Postfix rewrites
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addresses for many different purposes. Some are merely cosmetic, and some are
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necessary to deliver correctly formatted mail to the correct destination.
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Examples of address rewriting in Postfix are:
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* Transform an incomplete address into a complete address. For example,
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transform "username" into "username@example.com", or transform
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"username@hostname" into "username@hostname.example.com".
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* Replace an address by an equivalent address. For example, replace
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"username@example.com" by "firstname.lastname@example.com" when sending
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mail, and do the reverse transformation when receiving mail.
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* Replace an address by multiple addresses. For example, replace the address
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of an alias by the addresses listed under that alias.
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* Determine how and where to deliver mail for a specific address. For
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example, deliver mail for "username@example.com" with the smtp(8) delivery
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agent, to the hosts that are listed in the DNS as the mail servers for the
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Although Postfix currently has no address rewriting language, it can do
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surprisingly powerful address manipulation via table lookup. Postfix typically
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uses lookup tables with fixed strings to map one address to one or multiple
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addresses, and typically uses regular expressions to map multiple addresses to
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one or multiple addresses. Fixed-string lookup tables may be in the form of
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local files, or in the form of NIS, LDAP or SQL databases. The DATABASE_README
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document gives an introduction to Postfix lookup tables.
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Topics covered in this document:
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* Postfix address rewriting overview
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* Address rewriting when mail is received
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o Rewrite addresses to standard form
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o Canonical address mapping
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o Address masquerading
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o Automatic BCC recipients
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* Address rewriting when mail is delivered
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o Resolve address to destination
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o Mail transport switch
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o Relocated users table
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o Local alias database
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o Local per-user .forward files
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o Local catch-all address
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* Debugging your address manipulations
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PPoossttffiixx aaddddrreessss rreewwrriittiinngg oovveerrvviieeww
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The figure below zooms in on those parts of Postfix that are most involved with
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address rewriting activity. See the OVERVIEW document for an overview of the
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complete Postfix architecture. Names followed by a number are Postfix daemon
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programs, while unnumbered names represent Postfix queues or internal sources
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qmqpd(8) >- cleanup(8) -> incoming -> active -> qmgr(8) -< lmtp(8)
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The table below summarizes all Postfix address manipulations. If you're reading
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this document for the first time, skip forward to "Address rewriting when mail
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is received". Once you've finished reading the remainder of this document, the
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table will help you to quickly find what you need.
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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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|AAddddrreessss |SSccooppee|DDaaeemmoonn |GGlloobbaall ttuurrnn--oonn |SSeelleeccttiivvee ttuurrnn--ooffff |
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|mmaanniippuullaattiioonn| | |ccoonnttrrooll |ccoonnttrrooll |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Rewrite | |trivial-|append_at_myorigin, | |
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|addresses to|all |rewrite |append_dot_mydomain,|none |
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|standard |mail |(8) |swap_bangpath, | |
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|form | | |allow_percent_hack | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Canonical |all |cleanup | | |
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|address |mail |(8) |canonical_maps |receive_override_options|
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Address |all |cleanup |masquerade_domains |receive_override_options|
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|masquerading|mail |(8) | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Automatic |new |cleanup |always_bcc, | |
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|BCC |mail |(8) |sender_bcc_maps, |receive_override_options|
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|recipients | | |recipient_bcc_maps | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Virtual |all |cleanup |virtual_alias_maps |receive_override_options|
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|aliasing |mail |(8) | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Resolve |all |trivial-| | |
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|address to |mail |rewrite |none |none |
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|destination | |(8) | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Mail |all |trivial-| | |
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|transport |mail |rewrite |transport_maps |none |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Relocated |all |trivial-| | |
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|users table |mail |rewrite |relocated_maps |none |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Local alias |all |local(8)|alias_maps |none |
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|database |mail | | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Local per- | | | | |
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|user |all |local(8)|forward_path |none |
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|.forward |mail | | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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|Local catch-|all |local(8)|luser_relay |none |
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|all address |mail | | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _|_ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ |
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AAddddrreessss rreewwrriittiinngg wwhheenn mmaaiill iiss rreecceeiivveedd
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The cleanup(8) server receives mail from outside of Postfix as well as mail
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from internal sources such as forwarded mail, undeliverable mail that is
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bounced to the sender, and postmaster notifications about problems with the
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The cleanup(8) server transforms the sender, recipients and message content
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into a standard form before writing it to an incoming queue file. The server
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cleans up sender and recipient addresses in message headers and in the
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envelope, adds missing message headers such as From: or Date: that are required
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by mail standards, and removes message headers such as Bcc: that should not be
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present. The cleanup(8) server delegates the more complex address manipulations
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to the trivial-rewrite(8) server as described later in this document.
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Address manipulations at this stage are:
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* Rewrite addresses to standard form
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* Canonical address mapping
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* Address masquerading
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* Automatic BCC recipients
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RReewwrriittee aaddddrreesssseess ttoo ssttaannddaarrdd ffoorrmm
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Before the cleanup(8) daemon runs an address through any address mapping lookup
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table, it first rewrites the address to the standard
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"user@fully.qualified.domain" form, by sending the address to the trivial-
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rewrite(8) daemon. The purpose of rewriting to standard form is to reduce the
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number of entries needed in lookup tables.
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The Postfix trivial-rewrite(8) daemon implements the following hard-coded
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address manipulations:
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Rewrite "@hosta,@hostb:user@site" to "user@site"
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In case you wonder what this is, the address form above is called a
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route address, and specifies that mail for "user@site" be delivered via
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"hosta" and "hostb". Usage of this form has been deprecated for a long
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time. Postfix has no ability to handle route addresses, other than to
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strip off the route part.
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Rewrite "site!user" to "user@site"
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This feature is controlled by the boolean swap_bangpath parameter
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(default: yes). The purpose is to rewrite UUCP-style addresses to
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domain style. This is useful only when you receive mail via UUCP, but
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it probably does not hurt otherwise.
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Rewrite "user%domain" to "user@domain"
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This feature is controlled by the boolean allow_percent_hack parameter
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(default: yes). Typically, this is used in order to deal with
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monstrosities such as "user%domain@otherdomain".
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Rewrite "user" to "user@$myorigin"
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This feature is controlled by the boolean append_at_myorigin parameter
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(default: yes). You should never turn off this feature, because a lot
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of Postfix components expect that all addresses have the form
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If your machine is not the main machine for $myorigin and you wish to
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have some users delivered locally without going via that main machine,
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make an entry in the virtual alias table that redirects
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"user@$myorigin" to "user@$myhostname". See also the "delivering some
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users locally" section in the STANDARD_CONFIGURATION_README document.
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Rewrite "user@host" to "user@host.$mydomain"
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This feature is controlled by the boolean append_dot_mydomain parameter
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(default: yes). The purpose is to get consistent treatment of different
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forms of the same hostname.
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Some will argue that rewriting "host" to "host.$mydomain" is bad. That
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is why it can be turned off. Others like the convenience of having the
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local domain appended automatically.
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Rewrite "user@site." to "user@site" (without the trailing dot).
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A single trailing dot is silently removed. However, an address that
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ends in multiple dots will be rejected as an invalid address.
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CCaannoonniiccaall aaddddrreessss mmaappppiinngg
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The cleanup(8) daemon uses the canonical(5) tables to rewrite all addresses in
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message envelopes and in message headers. This is done for local and remote
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addresses. The mapping is useful to replace login names by "Firstname.Lastname"
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style addresses, or to clean up invalid domains in mail addresses produced by
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Canonical mapping is disabled by default. To enable, edit the canonical_maps
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parameter in the main.cf file and specify one or more lookup tables, separated
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by whitespace or commas.
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/etc/postfix/main.cf:
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canonical_maps = hash:/etc/postfix/canonical
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/etc/postfix/canonical:
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For static mappings as shown above, lookup tables such as hash:, ldap:, mysql:
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or pgsql: are sufficient. For dynamic mappings you can use regular expression
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tables. This requires that you become intimately familiar with the ideas
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expressed in regexp_table(5), pcre_table(5) and canonical(5).
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In addition to the canonical maps which are applied to both sender and
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recipient addresses, you can specify canonical maps that are applied only to
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sender addresses or to recipient addresses.
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/etc/postfix/main.cf:
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sender_canonical_maps = hash:/etc/postfix/sender_canonical
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recipient_canonical_maps = hash:/etc/postfix/recipient_canonical
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The sender and recipient canonical maps are applied before the common canonical
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Sender-specific rewriting is useful when you want to rewrite ugly sender
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addresses to pretty ones, and still want to be able to send mail to the those
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ugly address without creating a mailer loop.
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Canonical mapping can be turned off selectively for mail received by smtpd(8),
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qmqpd(8), or pickup(8), by overriding main.cf settings in the master.cf file.
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This feature is available in Postfix version 2.1 and later.
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/etc/postfix/master.cf:
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:10026 inet n - n - - smtpd
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-o receive_override_options=no_address_mapping
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Note: do not specify whitespace around the "=" here.
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AAddddrreessss mmaassqquueerraaddiinngg
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Address masquerading is a method to hide hosts inside a domain behind their
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mail gateway, and to make it appear as if the mail comes from the gateway
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itself, instead of from individual machines.
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Address masquerading is disabled by default, and is implemented by the cleanup
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(8) server. To enable, edit the masquerade_domains parameter in the main.cf
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file and specify one or more domain names separated by whitespace or commas.
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When Postfix tries to masquerade a domain, it processes the list from left to
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right, and processing stops at the first match.
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/etc/postfix/main.cf:
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masquerade_domains = foo.example.com example.com
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strips "any.thing.foo.example.com" to "foo.example.com", but strips
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"any.thing.else.example.com" to "example.com".
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A domain name prefixed with "!" means do not masquerade this domain or its
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/etc/postfix/main.cf:
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masquerade_domains = !foo.example.com example.com
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does not change "any.thing.foo.example.com" and "foo.example.com", but strips
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"any.thing.else.example.com" to "example.com".
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The masquerade_exceptions configuration parameter specifies what user names
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should not be subjected to address masquerading. Specify one or more user names
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separated by whitespace or commas.
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/etc/postfix/main.cf:
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masquerade_exceptions = root
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By default, Postfix makes no exceptions.
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Subtle point: by default, address masquerading is applied only to message
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headers and to envelope sender addresses, but not to envelope recipients. This
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allows you to use address masquerading on a mail gateway machine, while still
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being able to forward mail from outside to users on individual machines.
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In order to subject envelope recipient addresses to masquerading, too, specify
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(Postfix version 1.1 and later):
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/etc/postfix/main.cf:
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masquerade_classes = envelope_sender, envelope_recipient,
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header_sender, header_recipient
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If you rewrite the envelope recipient like this, Postfix will no longer be able
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to send mail to individual machines.
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Address masquerading can be turned off selectively for mail received by smtpd
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(8), qmqpd(8), or pickup(8), by overriding main.cf settings in the master.cf
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file. This feature is available in Postfix version 2.1 and later.
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/etc/postfix/master.cf:
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:10026 inet n - n - - smtpd
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-o receive_override_options=no_address_mapping
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Note: do not specify whitespace around the "=" here.
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AAuuttoommaattiicc BBCCCC rreecciippiieennttss
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After applying the canonical and masquerade mappings, the cleanup(8) daemon can
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generate optional BCC (blind carbon-copy) recipients. Postfix provides three
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Deliver a copy of all mail to the specified address. In Postfix
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versions before 2.1, this feature is implemented by smtpd(8), qmqpd(8),
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sender_bcc_maps = type:table
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Search the specified "type:table" lookup table with the envelope sender
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address for an automatic BCC address. This feature is available in
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Postfix 2.1 and later.
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recipient_bcc_maps = type:table
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Search the specified "type:table" lookup table with the envelope
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recipient address for an automatic BCC address. This feature is
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available in Postfix 2.1 and later.
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Note: automatic BCC recipients are produced only for new mail. To avoid mailer
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loops, automatic BCC recipients are not generated for mail that Postfix
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forwards internally, nor for mail that Postfix generates itself.
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Automatic BCC recipients (including always_bcc) can be turned off selectively
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for mail received by smtpd(8), qmqpd(8), or pickup(8), by overriding main.cf
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settings in the master.cf file. This feature is available in Postfix version
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/etc/postfix/master.cf:
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:10026 inet n - n - - smtpd
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-o receive_override_options=no_address_mapping
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Note: do not specify whitespace around the "=" here.
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VViirrttuuaall aalliiaassiinngg
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Before writing the recipients to the queue file, the cleanup(8) daemon uses the
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optional virtual(5) alias tables to redirect mail for recipients. The mapping
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affects only envelope recipient addresses; it has no effect on message headers
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or envelope sender addresses. Virtual alias lookups are useful to redirect mail
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for virtual alias domains to real user mailboxes, and to redirect mail for
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domains that no longer exist. Virtual alias lookups can also be used to
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transform " Firstname.Lastname " back into UNIX login names, although it seems
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that local aliases may be a more appropriate vehicle. See the VIRTUAL_README
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document for an overview of methods to host virtual domains with Postfix.
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Virtual aliasing is disabled by default. To enable, edit the virtual_alias_maps
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parameter in the main.cf file and specify one or more lookup tables, separated
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by whitespace or commas.
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/etc/postfix/main.cf:
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virtual_alias_maps = hash:/etc/postfix/virtual
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/etc/postfix/virtual:
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Addresses found in virtual alias maps are subjected to another iteration of
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virtual aliasing, but are not subjected to canonical mapping, in order to avoid
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For static mappings as shown above, lookup tables such as hash:, ldap:, mysql:
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or pgsql: are sufficient. For dynamic mappings you can use regular expression
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tables. This requires that you become intimately familiar with the ideas
403
expressed in regexp_table(5), pcre_table(5) and virtual(5).
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Note: automatic BCC recipients are produced only for new mail. To avoid mailer
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loops, automatic BCC recipients are not generated for mail that is forwarded
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internally, and are not generated for mail that is generated by Postfix itself.
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Virtual aliasing can be turned off selectively for mail received by smtpd(8),
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qmqpd(8), or pickup(8), by overriding main.cf settings in the master.cf file.
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This feature is available in Postfix version 2.1 and later.
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/etc/postfix/master.cf:
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:10026 inet n - n - - smtpd
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-o receive_override_options=no_address_mapping
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Note: do not specify whitespace around the "=" here.
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At this point the message is ready to be stored into the Postfix incoming
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AAddddrreessss rreewwrriittiinngg wwhheenn mmaaiill iiss ddeelliivveerreedd
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The Postfix queue manager sorts mail according to its destination and gives it
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to Postfix delivery agents such as local(8), smtp(8), or lmtp(8). Just like the
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cleanup(8) server, the Postfix queue manager delegates the more complex address
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manipulations to the trivial-rewrite(8) server.
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Address manipulations at this stage are:
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* Resolve address to destination
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* Mail transport switch
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* Relocated users table
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Each Postfix delivery agent tries to deliver the mail to its destination, while
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encapsulating the sender, recipients, and message content according to the
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rules of the SMTP, LMTP, etc. protocol. When mail cannot be delivered, it is
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either returned to the sender or moved to the deferred queue and tried again
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Address manipulations when mail is delivered via the local(8) delivery agent:
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* Local alias database
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* Local per-user .forward files
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* Local catch-all address
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The remainder of this document presents each address manipulation step in more
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detail, with specific examples or with pointers to documentation with examples.
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RReessoollvvee aaddddrreessss ttoo ddeessttiinnaattiioonn
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The Postfix qmgr(8) queue manager selects new mail from the incoming queue or
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old mail from the deferred queue, and asks the trivial-rewrite(8) address
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rewriting and resolving daemon where it should be delivered.
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As of version 2.0, Postfix distinguishes four major address classes. Each class
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has its own list of domain names, and each class has its own default delivery
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method, as shown in the table below. See the ADDRESS_CLASS_README document for
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the fine details. Postfix versions before 2.0 only distinguish between local
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delivery and everything else.
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_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _
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|DDeessttiinnaattiioonn ddoommaaiinn lliisstt |DDeeffaauulltt ddeelliivveerryy mmeetthhoodd|AAvvaaiillaabbiilliittyy|
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|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
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|$mydestination, $inet_interfaces,|$local_transport |Postfix 1.0 |
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|$proxy_interfaces | | |
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|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
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|$virtual_mailbox_domains |$virtual_transport |Postfix 2.0 |
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|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
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|$relay_domains |$relay_transport |Postfix 2.0 |
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|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
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|none |$default_transport |Postfix 1.0 |
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|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|_ _ _ _ _ _ _ _ _ _ _ _ |
477
MMaaiill ttrraannssppoorrtt sswwiittcchh
479
Once the trivial-rewrite(8) daemon has determined a default delivery method it
480
searches the optional transport(5) table for information that overrides the
481
message destination and/or delivery method. Typical use of the transport(5) is
482
to send mail to a system that is not connected to the Internet, or to use a
483
special SMTP client configuration for destinations that have special
484
requirements. See, for example, the STANDARD_CONFIGURATION_README and
485
UUCP_README documents, and the examples in the transport(5) manual page.
487
Transport table lookups are disabled by default. To enable, edit the
488
transport_maps parameter in the main.cf file and specify one or more lookup
489
tables, separated by whitespace or commas.
493
/etc/postfix/main.cf:
494
transport_maps = hash:/etc/postfix/transport
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RReellooccaatteedd uusseerrss ttaabbllee
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Next, the trivial-rewrite(8) address rewriting and resolving daemon runs each
499
recipient through the relocated(5) database. This table provides information on
500
how to reach users that no longer have an account, or what to do with mail for
501
entire domains that no longer exist. When mail is sent to an address that is
502
listed in this table, the message is returned to the sender with an informative
505
The relocated(5) database is searched after transport(5) table lookups, in
506
anticipation of transport(5) tables that can replace one recipient address by a
509
Lookups of relocated users are disabled by default. To enable, edit the
510
relocated_maps parameter in the main.cf file and specify one or more lookup
511
tables, separated by whitespace or commas.
515
/etc/postfix/main.cf:
516
relocated_maps = hash:/etc/postfix/relocated
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/etc/postfix/relocated:
519
username@example.com otheruser@elsewhere.tld
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As of Postfix version 2, mail for a relocated user will be rejected by the SMTP
522
server with the reason "user has moved to otheruser@elsewhere.tld". Older
523
Postfix versions will receive the mail first, and then return it to the sender
524
as undeliverable, with the same reason.
526
LLooccaall aalliiaass ddaattaabbaassee
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When mail is to be delivered locally, the local(8) delivery agent runs each
529
local recipient name through the aliases(5) database. The mapping does not
530
affect addresses in message headers. Local aliases are typically used to
531
implement distribution lists, or to direct mail for standard aliases such as
532
postmaster to real people. The table can also be used to map
533
"Firstname.Lastname" addresses to login names.
535
Alias lookups are enabled by default. The default configuration depends on the
536
operating system environment, but it is typically one of the following:
538
/etc/postfix/main.cf:
539
alias_maps = hash:/etc/aliases
540
alias_maps = dbm:/etc/aliases, nis:mail.aliases
542
The pathname of the alias database file is controlled with the alias_database
543
configuration parameter. The value is system dependent. Usually it is one of
546
/etc/postfix/main.cf:
547
alias_database = hash:/etc/aliases (4.4BSD, LINUX)
548
alias_database = dbm:/etc/aliases (4.3BSD, SYSV<4)
549
alias_database = dbm:/etc/mail/aliases (SYSV4)
551
An aliases(5) file can specify that mail should be delivered to a local file,
552
or to a command that receives the message in the standard input stream. For
553
security reasons, deliveries to command and file destinations are performed
554
with the rights of the alias database owner. A default userid, default_privs,
555
is used for deliveries to commands or files in "root"-owned aliases.
557
LLooccaall ppeerr--uusseerr ..ffoorrwwaarrdd ffiilleess
559
With delivery via the local(8) deliver agent, users can control their own mail
560
delivery by specifying destinations in a file called .forward in their home
561
directories. The syntax of these files is the same as with the local aliases(5)
562
file, except that the left-hand side of the alias (lookup key and colon) are
565
LLooccaall ccaattcchh--aallll aaddddrreessss
567
When the local(8) delivery agent finds that a message recipient does not exist,
568
the message is normally returned to the sender ("user unknown"). Sometimes it
569
is desirable to forward mail for non-existing recipients to another machine.
570
For this purpose you can specify an alternative destination with the
571
luser_relay configuration parameter.
573
Alternatively, mail for non-existent recipients can be delegated to an entirely
574
different message transport, as specified with the fallback_transport
575
configuration parameter. For details, see the local(8) delivery agent
578
Note: if you use the luser_relay feature in order to receive mail for non-UNIX
579
accounts, then you must specify:
581
/etc/postfix/main.cf:
582
local_recipient_maps =
584
(i.e. empty) in the main.cf file, otherwise the Postfix SMTP server will reject
585
mail for non-UNIX accounts with "User unknown in local recipient table". See
586
the LOCAL_RECIPIENT_README file for more information on this.
588
luser_relay can specify one address. It is subjected to "$name" expansions.
592
The bare username, without address extension, is prepended to
593
"@other.host". For example, mail for "username+foo" is sent to
594
"username@other.host".
597
The entire original recipient localpart, including address extension,
598
is prepended to "@other.host". For example, mail for "username+foo" is
599
sent to "username+foo@other.host".
602
The bare username, without address extension, is appended to
603
"sysadmin". For example, mail for "username+foo" is sent to
607
The entire original recipient localpart, including address extension,
608
is appended to "sysadmin". For example, mail for "username+foo" is sent
609
to "sysadmin+username+foo".
611
DDeebbuuggggiinngg yyoouurr aaddddrreessss mmaanniippuullaattiioonnss
613
With Postfix version 2.1 and later you can ask Postfix to produce mail delivery
614
reports for debugging purposes. These reports not only show sender/recipient
615
addresses after address rewriting and alias expansion or forwarding, they also
616
show information about delivery to mailbox, delivery to non-Postfix command,
617
responses from remote SMTP servers, and so on.
619
Postfix can produce two types of mail delivery reports for debugging:
621
* What-if: report what would happen, but do not actually deliver mail. This
622
mode of operation is requested with:
624
$ //uussrr//ssbbiinn//sseennddmmaaiill --bbvv aaddddrreessss......
625
Mail Delivery Status Report will be mailed to <your login name>.
627
* What happened: deliver mail and report successes and/or failures, including
628
replies from remote SMTP servers. This mode of operation is requested with:
630
$ //uussrr//ssbbiinn//sseennddmmaaiill --vv aaddddrreessss......
631
Mail Delivery Status Report will be mailed to <your login name>.
633
These reports contain information that is generated by Postfix delivery agents.
634
Since these run as daemon processes and do not interact with users directly,
635
the result is sent as mail to the sender of the test message. The format of
636
these reports is practically identical to that of ordinary non-delivery
639
As an example, below is the delivery report that is produced with the command
640
"sendmail -bv postfix-users@postfix.org". The first part of the report contains
641
human-readable text. In this case, mail would be delivered via mail.cloud9.net,
642
and the SMTP server replies with "250 Ok". Other reports may show delivery to
643
mailbox, or delivery to non-Postfix command.
645
Content-Description: Notification
646
Content-Type: text/plain
648
This is the Postfix program at host spike.porcupine.org.
650
Enclosed is the mail delivery report that you requested.
654
<postfix-users@postfix.org>: delivery via mail.cloud9.net[168.100.1.4]: 250
657
The second part of the report is in machine-readable form, and includes the
658
following information:
660
* The envelope sender address (wietse@porcupine.org).
661
* The envelope recipient address (postfix-users@postfix.org). If the
662
recipient address was changed by Postfix then Postfix also includes the
663
original recipient address.
664
* The delivery status.
666
Some details are still preliminary and will change as Postfix implements the
667
DSN (delivery status notification) standards.
669
Content-Description: Delivery report
670
Content-Type: message/delivery-status
672
Reporting-MTA: dns; spike.porcupine.org
673
X-Postfix-Queue-ID: 84863BC0E5
674
X-Postfix-Sender: rfc822; wietse@porcupine.org
675
Arrival-Date: Tue, 13 Apr 2004 19:27:43 -0400 (EDT)
677
Final-Recipient: rfc822; postfix-users@postfix.org
680
Diagnostic-Code: X-Postfix; delivery via mail.cloud9.net[168.100.1.4]: 250
683
The third part of the report contains the message that Postfix would have
684
delivered, including From: and To: message headers, so that you can see any
685
effects of address rewriting on those. Mail submitted with "sendmail -bv" has
686
no body content so none is shown in the example below.
688
Content-Description: Message
689
Content-Type: message/rfc822
691
Received: by spike.porcupine.org (Postfix, from userid 1001)
692
id 84863BC0E5; Tue, 13 Apr 2004 19:27:43 -0400 (EDT)
694
To: postfix-users@postfix.org
695
Message-Id: <20040413232743.84863BC0E5@spike.porcupine.org>
696
Date: Tue, 13 Apr 2004 19:27:43 -0400 (EDT)
697
From: wietse@porcupine.org (Wietse Venema)
added
removed
README_FILES/ADDRESS_REWRITING_README
