table_redis

This manual page documents the file format of redis tables used by the smtpd(8) mail daemon.

The format described here applies to tables as defined in smtpd.conf(5).

A Redis table allows the storing of usernames, passwords, aliases, and domains in a redis server.

The table is used by smtpd(8) when authenticating a user, when user information such as user-id and/or home directory is required for a delivery, when a domain lookup may be required, and/or when looking for an alias.

A Redis table consists of one Redis Databases with one or more keys.

If the table is used for authentication, the password should be encrypted using the crypt(3) function. Such passwords can be generated using the encrypt(1) utility or smtpctl(8) encrypt command.

master

This is the IP of the master redis server. To connect via an unix socket use unix:/path/to/sock The default is 127.0.0.1

master_port

This is the port used to connect to the master redis server. The default is 6379

slave

This is the IP of the slave redis server, if any. To connect via an unix socket use unix:/path/to/sock

slave_port

This is the port used to connect to the slave redis server if any.

database

The database number to use. The default is 0.

password

The password to use to authenticate to the redis server if any.

query_domain

This is used to provide a query for a domain query call. All the '%s' are replaced with the appropriate data, in this case it would be the right hand side of the SMTP address. This expects one string to be returned with a matching domain name.

query_userinfo

This is used to provide a query for looking up user information. All the '%s' are replaced with the appropriate data, in this case it would be the left hand side of the SMTP address. This expects three fields to be returned an int containing a UID, an int containing a GID and a string containing the home directory for the user.

query_credentials

This is used to provide a query for looking up credentials. All the '%s' are replaced with the appropriate data, in this case it would be the left hand side of the SMTP address. the query expects that there are two strings returned one with a user name one with a password in encrypted format.

query_alias

This is used to provide a query to look up aliases. All the '%s' are replaced with the appropriate data, in this case it would be the left hand side of the SMTP address. This expects one string to be returned with the user name the alias resolves to. If the query returns an array, all the data will be concatenated into one string with ',' as a separator

query_mailaddr

This is used to provide a query to check if a mail address exists. All the '%s' are replaced with the appropriate data, in this case it would be the SMTP address. This expects an integer as a reply, 0 = false and 1 = true

Due to the nature of redis, multiple schemas can be used. Those provided here a known to work.

domain

Using a set for the domains:

# redis-cli sadd domains example.net

in the redis table configuration file:

query_domain SISMEMBER domains %s

userinfo

Hash works well for users

# redis-cli HSET user:foo uid 1001

# redis-cli HSET user:foo gid 1001

# redis-cli HSET user:foo maildir /mail/foo

in the redis table configuration file :

query_userinfo HMGET user:%s uid gid maildir

credentials

We can extend the hash for our user to put credential in it

# redis-cli HSET user:foo login foo

# redis-cli HSET user:foo passwd encrypted_password

in the redis table configuration file:

query_credentials HMGET user:%s login passwd

alias

Using redis sorted list:

# redis-cli LPUSH aliases:foo@example.net foo

# redis-cli LPUSH aliases:bar@example.net foo

in the redis table configuration file:

query_alias LRANGE aliases:%s 0 -1

mailaddr

Using a set for the addresses:

# redis-cli sadd mailaddr foo@example.net

in the redis table configuration file:

query_mailaddr SISMEMBER mailaddr %s

encrypt(1), smtpd.conf(5), smtpctl(8), smtpd(8)

The first version of table_redis was written in 2015. It was converted to the stdio protocol in 2024.

table_redis was initially written by Emmanuel Vadot <elbarto@bocal.org>. The conversion to the stdio table protocol was done by Omar Polo <op@openbsd.org>.