TABLE(5) File Formats Manual TABLE(5)
NAME
table - format description for smtpd tables
DESCRIPTION
This manual page documents the file format for the various tables used in
the smtpd(8) mail daemon.
The format described here applies to tables as defined in smtpd.conf(5).
TABLE TYPES
There are two types of tables: lists and mappings. A list consists of a
series of values, while a mapping consists of a series of keys and their
associated values. The following illustrates how to declare them as
static tables:
table mylist { value1, value2, value3 }
table mymapping { key1 = value1, key2 = value2, key3 = value3 }
When using a `file' table, a list will be written with each value on a
line by itself.
value1
value2
value3
A mapping will be written with each key and value on a line, whitespace
and an optional colon separating both columns:
key1: value1
key2 value2
key3 value3
Blank lines, leading and trailing spaces and tabs are ignored. Lines
whose first non-space character is a hash mark (`#') are comments and are
ignored. To force the parsing of a file table as a list rather than a
mapping, use this special comment:
# @list
A file table can be converted to a Berkeley database using the makemap(8)
utility with no syntax change.
Tables using a `file' or Berkeley DB backend will be referenced as
follows:
table name file:/path/to/file
table name db:/path/to/file.db
Aliasing tables
Aliasing tables are mappings that associate a recipient to one or many
destinations. They can be used in two contexts: primary domain aliases
and virtual domain mapping.
action name method alias
action name method virtual
In a primary domain context, the key is the user part of the recipient
address, whilst the value is one or many recipients as described in
aliases(5):
user1 otheruser
user2 otheruser1,otheruser2
user3 otheruser@example.com
In a virtual domain context, the key is either a user part, a full email
address or a catch-all, following selection rules described in
smtpd.conf(5), and the value is one or many recipients as described in
aliases(5):
user1 otheruser
user2@example.org otheruser1,otheruser2
@example.org otheruser@example.com
@ catchall@example.com
The following directive shares the same table format, but with a
different meaning. Here, the user is allowed to send mail from the
listed addresses:
listen on interface auth [...] senders
Domain tables
Domain tables are simple lists of domains or hosts.
match for domain action name
match helo [...] action name
In that context, the list of domains will be matched against the
recipient domain or against the HELO name advertised by the sending host,
respectively. For `static', `file' and dbopen(3) backends, a wildcard
may be used so the domain table may contain:
example.org
*.example.org
Credentials tables
Credentials tables are mappings of credentials. They can be used in two
contexts:
listen on interface tls [...] auth
action name relay host relay-url auth
In a listener context, the credentials are a mapping of username and
encrypted passwords:
user1 $2b$10$hIJ4QfMcp.90nJwKqGbKM.MybArjHOTpEtoTV.DgLYAiThuoYmTSe
user2 $2b$10$bwSmUOBGcZGamIfRuXGTvuTo3VLbPG9k5yeKNMBtULBhksV5KdGsK
The passwords are to be encrypted using the smtpctl(8) encrypt
subcommand.
In a relay context, the credentials are a mapping of labels and
username:password pairs:
label1 user:password
The label must be unique and is used as a selector for the proper
credentials when multiple credentials are valid for a single destination.
The password is not encrypted as it must be provided to the remote host.
Netaddr tables
Netaddr tables are lists of IPv4 and IPv6 network addresses. They can
only be used in the following context:
match from src action name
When used as a "from source", the address of a client is compared to the
list of addresses in the table until a match is found.
A netaddr table can contain exact addresses or netmasks, and looks as
follow:
192.168.1.1
::1
ipv6:::1
192.168.1.0/24
Userinfo tables
Userinfo tables are used in rule context to specify an alternate
userbase, mapping virtual users to local system users by UID, GID and
home directory.
action name method userbase
A userinfo table looks as follows:
joe 1000:100:/home/virtual/joe
jack 1000:100:/home/virtual/jack
In this example, both joe and jack are virtual users mapped to the local
system user with UID 1000 and GID 100, but different home directories.
These directories may contain a forward(5) file. This can be used in
conjunction with an alias table that maps an email address or the domain
part to the desired virtual username. For example:
joe@example.org joe
jack@example.com jack
Source tables
Source tables are lists of IPv4 and IPv6 addresses. They can only be
used in the following context:
action name relay src
Successive queries to the source table will return the elements one by
one.
A source table looks as follow:
192.168.1.2
192.168.1.3
::1
::2
ipv6:::3
ipv6:::4
Mailaddr tables
Mailaddr tables are lists of email addresses. They can be used in the
following contexts:
match mail-from action name
match rcpt-to action name
A mailaddr entry is used to match an email address against a username, a
domain or a full email address. A "*" wildcard may be used in part of
the domain name.
A mailaddr table looks as follow:
user
@domain
user@domain
user@*.domain
Addrname tables
Addrname tables are used to map IP addresses to hostnames. They can be
used in both listen context and relay context:
listen on interface hostnames
action name relay helo-src
In listen context, the table is used to look up the server name to
advertise depending on the local address of the socket on which a
connection is accepted. In relay context, the table is used to determine
the hostname for the HELO sequence of the SMTP protocol, depending on the
local address used for the outgoing connection.
The format is a mapping from inet4 or inet6 addresses to hostnames:
::1 localhost
127.0.0.1 localhost
88.190.23.165 www.opensmtpd.org
SEE ALSO
smtpd.conf(5), makemap(8), smtpd(8)
Linux 6.8.7-arch1-1 December 27, 2023 Linux 6.8.7-arch1-1