CANONICAL(5) CANONICAL(5)
NAME
canonical - format of Postfix canonical table
SYNOPSIS
postmap /etc/postfix/canonical
DESCRIPTION
The optional canonical file specifies an address mapping
for local and non-local addresses. The mapping is used by
the cleanup(8) daemon. The address mapping is recursive.
The file serves as input to the postmap(1) command. The
result, an indexed file in dbm or db format, is used for
fast searching by the mail system. After an update it may
take a minute or so before the change becomes visible.
Issue a postfix reload command to eliminate the delay.
The canonical mapping affects both message header
addresses (i.e. addresses that appear inside messages) and
message envelope addresses (for example, the addresses
that are used in SMTP protocol commands). Think Sendmail
rule set S3, if you like.
Typically, one would use the canonical table to replace
login names by Firstname.Lastname, or to clean up
addresses produced by legacy mail systems.
The canonical mapping is not to be confused with virtual
domain support. Use the virtual(5) map for that purpose.
The canonical mapping is not to be confused with local
aliasing. Use the aliases(5) map for that purpose.
The format of the canonical table is as follows, mappings
being tried in the order as listed in this manual page:
blanks and comments
Blank lines are ignored, as are lines beginning
with `#'.
user@domain address
user@domain is replaced by address. This form has
the highest precedence.
This form useful to clean up addresses produced by
legacy mail systems. It can also be used to pro-
duce Firstname.Lastname style addresses, but see
below for a simpler solution.
user address
user@site is replaced by address when site is equal
to $myorigin, when site is listed in $mydestina-
tion, or when it is listed in $inet_interfaces.
1
CANONICAL(5) CANONICAL(5)
This form is useful for replacing login names by
Firstname.Lastname.
@domain address
Every address in domain is replaced by address.
This form has the lowest precedence.
In all the above forms, when address has the form @other-
domain, the result is the same user in otherdomain.
ADDRESS EXTENSION
When table lookup fails, and the address localpart con-
tains the optional recipient delimiter (e.g.,
user+foo@domain), the search is repeated for the unex-
tended address (e.g. user@domain), and the unmatched
extension is propagated to the result of table lookup. The
matching order is: user+foo@domain, user@domain, user+foo,
user, and @domain.
BUGS
The table format does not understand quoting conventions.
CONFIGURATION PARAMETERS
The following main.cf parameters are especially relevant
to this topic. See the Postfix main.cf file for syntax
details and for default values. Use the postfix reload
command after a configuration change.
canonical_maps
List of canonical mapping tables.
recipient_canonical_maps
Address mapping lookup table for envelope and
header recipient addresses.
sender_canonical_maps
Address mapping lookup table for envelope and
header sender addresses.
Other parameters of interest:
inet_interfaces
The network interface addresses that this system
receives mail on.
masquerade_domains
List of domains that hide their subdomain struc-
ture.
masquerade_exceptions
List of user names that are not subject to address
masquerading.
2
CANONICAL(5) CANONICAL(5)
mydestination
List of domains that this mail system considers
local.
myorigin
The domain that is appended to locally-posted mail.
owner_request_special
Give special treatment to owner-xxx and xxx-request
addresses.
SEE ALSO
cleanup(8) canonicalize and enqueue mail
postmap(1) create mapping table
virtual(5) virtual domain mapping
LICENSE
The Secure Mailer license must be distributed with this
software.
AUTHOR(S)
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
3