Docker mailserver
This mailserver setup follows Workaround's SPmail guide for Debian 12 “Bookworm”. Key changes are that instead of installing on Debian 11 virtual machine1, with a Maria mysql database2, this setup is for installation on latest Alpine linux Docker image with s6-rc init using maria database. I toyed with sqlite and basically got it functional, however the support apps do not function with sqlite.
As this follows Workaround's SPmail guide for Debian 12 “Bookworm”, significant amounts of text have been copied and generally modified from there. I hereby credit Workaround's author Christoph Haas. Furthermore Christoph's guide is very descriptive and should be referenced to get a better understanding of how to put together a mailserver.
- Use of virtual machines is much more common these days than base metal for applications. However Workarounds Debian email server could be loaded on base metal.
- The database requirements for a small mailserver with a few dozen domains, with each domain having hundreds of emails and aliases is well within the capacity of the sqlite database. The use of a full multi user server / client relational database is not necessary, particularly for a Docker based server implementation. See SQLite vs MySQL vs PostgreSQL: A Comparison Of Relational Database Management Systems
I got the Docker emailer server functional mid 2023. It still needs some more work. I recently went through and clean up some non-fatal errors in the configuration that were showing in the logs, mid 2024. Currently I run the mail server 2 containers, I would rather have it all in one container. The email server could also have some more optimisations performed.
Dockerfile
I go annoyed with the messy UID and GID and found this reference to attempt to standardise upon. Sadly there seems to be no comprehensive standard!
- Distribution List of Ports (information only)
- Archlinux DeveloperWiki:UID / GID Database
- Red Hat 37.3. Standard Users
References
- Docker
packages
working
Required for server:
- sqlite ⇒
/usr/bin/sqlite3
- postfix ⇒
/usr/sbin/postfix
- postfix-sqlite
postfix-sqlite.so
plugin? - #dovecot ⇒ #main dovecot included in dovecot-sqlite
- dovecot-sqlite ⇒
/usr/sbin/dovecot
- #dovecot-pop3 ⇒ #Only if need pop3 connectivit2y
- dovecot-imapd ⇒ plugin?
- dovecot-lmtpd ⇒ plugin?
- dovecot-pigeonhole-plugin ⇒ plugin?
- apache2 ⇒
/usr/sbin/httpd
- php ⇒
/usr/bin/php
→/usr/bin/php81
So the standard php package currently links to php81 at this time of writing. - Adminer is downloaded separately
adminer
is a single php file program to administer database programs including sqlite - rspamd ⇒
/usr/sbin/rspamd
The email spam removing daemon - swaks ⇒
/user/bin/swaks
Seems to only be in testing repository, use following to loadswaks --repository=http://dl-cdn.alpinelinux.org/alpine/edge/testing/
- mutt ⇒
/usr/bin/mutt
- jq ⇒
/usr/bin/jq
To assist with working in container:
- util-linux ⇒ adds some addition utilities to Alpine, e.g.
whereis
This is not required for the final package and can be commented out of the Dockerfile. - pwgen ⇒
pwgen
generates encrypted passwords - vim ⇒ because it is nicer to use than
vi
- less ⇒ because sometimes it is nicer to use than
cat
(it looks like util-linux includes themore
command.less
seems more full featured and what I am use to. It looks likeless
will not work properly unlessexport TERM=rxvt
is used. Hmmm… unimpressed
alias
I could not get the alias command to work in Alpine shell. I tried /etc/profile and /etc/profile.d to no avail. So the following seems to meet my needs:
- create file
ll.sh
#!/bin/sh exec ls -la "$@"
- chmod +x ll.sh to allow to to be an executable.
- Copy the ll.sh file to /bin/ll or link it
/bin/ln -s /app/scripts/ll.sh /bin/ll
sqlite
sqlite commands
sqlite3 /app/mailserver.db
to start sqlite and create or open mailserver.db..open /app/mailserver.db
to open mailserver.db.tables
to list tables in a database- To list tables from sqlite_schema:
SELECT name FROM sqlite_schema WHERE TYPE ='table' AND name NOT LIKE 'sqlite_%';
SELECT * FROM table_name;
to query all data from a table.
virtual_domains
This table just holds the list of domains that you will use as virtual_mailbox_domains in Postfix.
Column | Purpose |
---|---|
id | A unique number identifying each row. It is added by the database automatically. |
name | The name of the domain you want to receive email for. |
This SQL statement creates a table like that:
sql code
CREATE TABLE IF NOT EXISTS `virtual_domains` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `name` VARCHAR(50) NOT NULL, PRIMARY KEY (`id`) ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
sqlite code
CREATE TABLE IF NOT EXISTS 'virtual_domains' ( id INTEGER PRIMARY KEY, name TEXT NOT NULL UNIQUE );
DROP TABLE IF EXISTS virtual_domains;
will delete the table.
virtual_users
The next table contains information about your users. Every mail account takes up one row.
Column | Purpose |
---|---|
id | A unique number identifying each row. It is added by the database automatically. |
domain_id | Contains the number of the domain’s id in the virtual_domains table. This is called a foreign key. A “delete cascade” makes sure that if a domain is deleted that all user accounts in that domain are also deleted to avoid orphaned rows. |
The email address of the mail account. | |
password | The hashed password of the mail account. It is prepended by the password scheme. By default it is {BLF-CRYPT} also known as bcrypt which is considered very secure. Previous ISPmail guides used {SHA256-CRYPT} or even older crypt schemes. Prepending the password field the hashing algorithm in curly brackets allows you to have different kinds of hashes. So you can easily migrate your old passwords without locking out users. Users with older schemes should get a new password if possible to increase security. |
quota | The number of bytes that this mailbox can store. You can use this value to limit how much space a mailbox can take up. The default value is 0 which means that there is no limit. |
This is the appropriate SQL query to create that table:
sql code
CREATE TABLE IF NOT EXISTS `virtual_users` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `domain_id` INT(11) NOT NULL, `email` VARCHAR(100) NOT NULL, `password` VARCHAR(150) NOT NULL, `quota` BIGINT(11) NOT NULL DEFAULT 0, PRIMARY KEY (`id`), UNIQUE KEY `email` (`email`), FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
sqlite code
CREATE TABLE IF NOT EXISTS `virtual_users` ( `id` INTEGER PRIMARY KEY, `domain_id` INTEGER NOT NULL, `email` TEXT NOT NULL UNIQUE, `password` TEXT NOT NULL, `quota` INTEGER NOT NULL DEFAULT 0, FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE );
virtual_aliases
The last table contains forwardings from an email address to other email addresses.
Field | Purpose |
---|---|
id | A unique number identifying each row. It is added by the database automatically. |
domain_id | Contains the number of the domain’s id in the virtual_domains table again. |
source | The email address that the email was actually sent to. In case of catch-all addresses (that accept any address in a domain) the source looks like “@example.org”. |
destination | The email address that the email should instead be sent to. |
This is the required SQL query you need to run:
sql
CREATE TABLE IF NOT EXISTS `main.virtual_aliases` ( `id` INT(11) NOT NULL AUTO_INCREMENT, `domain_id` INT(11) NOT NULL, `source` VARCHAR(100) NOT NULL, `destination` VARCHAR(100) NOT NULL, PRIMARY KEY (`id`), FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE ) ENGINE=InnoDB DEFAULT CHARSET=utf8;
sqlite
CREATE TABLE IF NOT EXISTS `virtual_aliases` ( `id` INTEGER PRIMARY KEY, `domain_id` INTEGER NOT NULL, `source` TEXT NOT NULL, `destination` TEXT NOT NULL, FOREIGN KEY (domain_id) REFERENCES virtual_domains(id) ON DELETE CASCADE );
sqlite example test data
The following test dat acan be used to test the data returns from postfix.
REPLACE INTO virtual_domains (id,name) VALUES ('1','example.org'); REPLACE INTO virtual_users (id,domain_id,password,email) VALUES ('1', '1', '{BLF-CRYPT}$2y$05$.WedBCNZiwxY1CG3aleIleu6lYjup2CIg0BP4M4YCZsO204Czz07W', 'john@example.org'); REPLACE INTO virtual_aliases (id,domain_id,SOURCE,destination) VALUES ('1', '1', 'jack@example.org', 'john@example.org');
This sample data should be deleted before using the mailserver live.
DELETE FROM mailserver.virtual_domains WHERE name='example.org';
references
- sqlitetutorial.net SQLite Tutorial
- sqlitetutorial.net SQLite Cheat Sheet
- tutorialspoint.com SQLite Tutorial
- database.guide sqlite
mariadb
- Used linuxserver.io mariadb image
docker exec -it mail_db /bin/bash
-
- Un-comment
bind-address=0.0.0.0
near end of config file incustom.cnf
(.config_sql/custom.cnf
) grant select on mailserver.* to 'mailserver'@'172.%' identified by 'PASSWORD';
The Docker internal network is on 172.
- php modules required do not seem to be defined anywhere, I used the following php modules
I am not sure if all these modules are required. Those with # are not required for Adminer. ISPMailAdmin requires bcmath. Adminer seemed to work without mysqli and mysqlnd.
mariadb sql commands
SELECT User, Host FROM mysql.user;
this shows all the user(s) and their host(s)grant select on mailserver.* to 'mailserver'@'172.16.0.0/255.240.0.0' identified by 'password.x.y.z.';
This creates the usermailserver
, assignsselect
level privileges and password. When I used CIDR '172.16.0.0/12' Mariadb did not seem to allow access where as subnet mask, '172.16.0.0/255.240.0.0' did function. Strange….grant all privileges on mailserver.* to 'mailadmin'@'172.16.0.0/255.240.0.0' identified by 'password.w.x.y.';
This creates the usermailadmin
, assigns all privileges and password.GRANT ALL PRIVILEGES ON mailserver.* TO 'mailadmin'@'172.16.0.0/255.240.0.0';
This grantsall
privileges on database mailserver to user mailadmin at defined host.REVOKE ALL PRIVILEGES, grant option from 'mailserver'@'172.%';
This revokes all privileges from user mailserver'@'172.%.SELECT User, Host FROM mysql.user WHERE Host <> 'localhost';
Filters the user / host list.drop user 'mailserver'@'172.16.0.0/255.240.0.0';
This drops the user.show grants for 'mailserver'@'172.16.0.0/255.240.0.0';
This shows the privileges for the specified user.
Many of the problems that I had trying to get Adminer and ISPMailAdmin operation related to access privileges on the Mariadb. I should have read and understood the ISPMail Preparing the database section more carefully. Some keypoints:
- The mailadmin user was linked to localhost and granted all privileges
- In mariadb localhost uses the socket file
/var/run/mysqld/mysqld.sock
This tends to be more secure than the TCP connection and the ISPmail uses this user for database administrative control.
- The mailserver user was linked to 127.0.0.0 and granted select privilege only
- In mariadb an IP host uses TCP to communicate. In ISPmail Postfix is set to use this interface, effectively read only (select privilege only).
- I am using in Docker with multiple separate containers.
- As these Docker containers are operated on a common Linux server the socket file is effectively one a common machine and could be shared across multiple containers. I have successfully performed this with separate Nginx / PHP-FPM (fastCGI) containers sharing a common socket file.
- Because the database is running in a separate container to the Nginx web server there is no common localhost or 127.0.0.1 available to share.
- Docker internal networking uses 172.16.0.0/12 (subnet mask 255.240.0.0), supposedly recent version of mysql support this notation (How to grant remote access to MySQL for a whole subnet?). Hence, grant [select|all] on mailserver.* to 'mailserver'@'172.16.0.0/12' identified by 'PASSWORD';
- I need to consider the following users
- Local mail_db container administrative access, continue to use 'mailadmin'@'localhost'.
- Docker stack container administrative access to adjust database with suitable table edit/create privilege, perhaps, 'mailstackadmin'@
172.16.0.0/12'. *Docker stack container postfix select only access to adjust database with suitable table edit/create privilege, 'mailserver'@
172.16.0.0/12'.
adminer
I will setup DNS and Traefik for this to be mailsql.local.kptree.net
. This will only be accessible on the LAN.
ISPmail Admin
I will setup DNS and Traefik for this to be mailadmin.local.kptree.net
. This will only be accessible on the LAN.
Admin user is mailserver with associated password.
adminer
phpMyAdmin is a web based mysql management interface.
adminer is a web based single php file database manager, that is suitable for many type of databases, including sqlite and being only a single file is easier to implement. Copy the latest version of adminer to .config/adminer
To test:
192.168.1.14:8910 database: SQLite 3 user: password: standard database: /app/mailserver.db
There is another program call SQLiteStudio. This look looks like a full GUI program, that will probably not be suitable for installation on a Docker mailserver. Noted.
Adminer needs a few php modules to run, session and pdo_sqlite, apk packages: php$phpverx-session, php$phpverx-pdo_sqlite, php$phpverx-sqlite3. Also Adminer does not like working with Sqlite without forcing some kind of password protect. Hence the Adminer plugin module and password-less plugin need to be used.
It seems that Apache2 php runs more efficiently if the php-fpm module is used and setup. See Alpine Apache with php-fpm
postfix
/etc/postfix
/ # postconf mail_version mail_version = 3.7.4
postconf -d
to print default parameterspostconf -n
to print parameters specifically changed in main.cf
Making Postfix get its information from the sqlite database
virtual_mailbox_domains
A mapping in Postfix is just a table that contains a left-hand side (LHS) and a right-hand side (RHS). To make Postfix get information about virtual domains from the database we need to create a ‘cf’ file (configuration file). Start by creating a file called /etc/postfix/sqlite-virtual-mailbox-domains.cf for the virtual_mailbox_domains mapping that contains:
dbpath = /app/mailserver.db query = SELECT 1 FROM virtual_domains WHERE name='%s'
Imagine that Postfix receives an email for somebody@example.org and wants to find out if example.org is a virtual mailbox domain. It will run the above SQL query and replace ‘%s’ by ‘example.org’. If it finds such a row in the virtual_domains table it will return a ‘1’. Actually it does not matter what exactly is returns as long as there is a result.
Now you need to make Postfix use this database mapping: postconf virtual_mailbox_domains=sqlite:/etc/postfix/sqlite-virtual-mailbox-domains.cf
The “postconf” command conveniently adds configuration lines to your /etc/postfix/main.cf file. It also activates the new setting instantly so you do not have to reload the Postfix process.
The test data you created earlier added the domain “example.org” as one of your mailbox domains. Let’s ask Postfix if it recognizes that domain: postmap -q example.org sqlite:/etc/postfix/sqlite-virtual-mailbox-domains.cf
You should get ‘1’ as a result. That means your first mapping is working. Feel free to try that with other domains after the -q in that line. You should not get a response
virtual_mailbox_maps
The virtual_mailbox_maps which is mapping email addresses (left-hand side) to the location of the user’s mailbox on your hard disk (right-hand side). Postfix has a built-in transport service called “virtual” that can receive the email and store it into the recipient’s email directory. But we will not make Postfix save the email to disk. We will delegate that to Dovecot as it allows us better control.
All that Postfix needs to know is whether an email address belongs to a valid mailbox. That simplifies things a bit because we just need the left-hand side of the mapping.
Similar to the above virtual_domains mapping you need an SQL query that searches for an email address and returns “1” if it is found.
To accomplish that please create another configuration file at /etc/postfix/sqlite-virtual-mailbox-maps.cf
:
dbpath = /app/mailserver.db query = SELECT 1 FROM virtual_users WHERE email='%s'
Tell Postfix that this mapping file is supposed to be used for the virtual_mailbox_maps mapping: postconf virtual_mailbox_maps=sqlite:/etc/postfix/sqlite-virtual-mailbox-maps.cf
Test if Postfix is happy with this mapping by asking it where the mailbox directory of our john@example.org user would be: postmap -q john@example.org sqlite:/etc/postfix/sqlite-virtual-mailbox-maps.cf
Again you should get “1” back which means that john@example.org is an existing virtual mailbox user on your server. Very good. Later when we deal with the Dovecot configuration we will also use the password field but Postfix does not need it right here.
virtual_alias_maps
The virtual_alias_maps mapping is used for forwarding emails from one email address to one or more others. In the database multiple targets are achieved by using multiple rows.
Create another “.cf” file at /etc/postfix/sqlite-virtual-alias-maps.cf
:
dbpath = /app/mailserver.db query = SELECT destination FROM virtual_aliases WHERE SOURCE='%s'
Make Postfix use this database mapping: postconf virtual_alias_maps=sqlite:/etc/postfix/sqlite-virtual-alias-maps.cf
Test if the mapping file works as expected: postmap -q jack@example.org sqlite:/etc/postfix/sqlite-virtual-alias-maps.cf
You should see the expected destination: john@example.org
So if Postfix receives an email for jack@example.org it will redirect it to john@example.org.
postfix start/stop
Basic postfix control are:
postfix start
to start postfix in backgroundpostfix start-fg
to start postfix in the foregroundpostfix stop
to stop postfixpostfix reload
to reload configurationpostfix status
to return current postfix operating status
It looks a shell script is used to control Postfix, in Alpine is is located here
systemd
The systemd service script is a hoot!, it seems to do nothing meaningful.
/lib/systemd/system/postfix.service
Look like postfix is started from /etc/init.d/postfix
. This script notes the following options, “Usage: /etc/init.d/postfix {start|stop|restart|reload|flush|check|abort|force-reload|status}”
Alpine
/usr/libexec/postfix/postfix-script
/usr/sbin/postfix
postfix library modules/etc/postfix
configuration files
s6 setup
The s6 rc run file:
Postfix logging
Alpine posfix would seem to be setup to use postlogd, as master.cf has the following line already configured: postlog unix-dgram n - n - 1 postlogd
. Hence the following does not need to be used: /bin/echo 'postlog unix-dgram n - n - 1 postlogd' >> '/etc/postfix/master.cf'
The postfix.log
warning “postfix/postfix-script[228]: warning: group or other writable: /etc/postfix/./master.cf” is probably as the noted file has been setup using a symlink. As it is a warning only no further concern.
/etc/postfix/aliases
I get an error when recreating the container; “error: open database /etc/postfix/aliases.lmdb: No such file or directory” The postfix command recreates the missing/corupt aliases.lmdb file; newaliases
.I added this to my Docker container startup script. This solved the problem, but not sure if this is the right way to do this.
Postfix References
- Postfix:
- Postfix logging references
- Other Postfix resources:
- Gentoo Linux: Complete Virtual Mail Server
- Is there any way to run Postfix in foreground? This is interesting as it infers that postfix was originally reliant upon syslog.
dovecot
/etc/dovecot/conf.d
/ # dovecot --version 2.3.20 (80a5ac675d)
doveconf -d
to print default parametersdoveconf -n
to print parameters specifically changed in main.cf
dovecot database configuration and testing
database setup: /etc/dovecot/dovecot-sql.conf.ext
See Dovecot howto on sqlite setup Dovecot configuration sqlite, linked from Dovecot HOWTOs / Examples / Tutorials
You will find this file well documented although all configuration directives are commented out. Add these lines at the bottom of the file:
driver = sqlite CONNECT = /app/mailserver.db user_query = SELECT email AS USER, \ '*:bytes=' || quota AS quota_rule, \ '/var/vmail/%d/%n' AS home, \ 5000 AS uid, 5000 AS gid \ FROM virtual_users WHERE email='%u' password_query = SELECT password FROM virtual_users WHERE email='%u' iterate_query = SELECT email AS USER FROM virtual_users
Notes:
- The Dovecot file uses the
\
at the end of each line to indicate the command continues on to the next line. Sqlite does not allow this. - The mysql concat command syntax is || for sqlite
- connect = is the full path to the sqlite mailserver database
Dovecot database testing
Testing directly within sqlite3:
- Open the sqlite3 database at the command line sqlite3 /app/mailserver.db
- user_query: SELECT email AS USER, '*:bytes=' || quota AS quota_rule, '/var/vmail/%d/%n' AS home, 5000 AS uid, 5000 AS gid FROM virtual_users WHERE email='john@example.org';
- output example on success: john@example.org|*:bytes=0|/var/vmail/%d/%n|5000|5000
- password_query: SELECT password FROM virtual_users WHERE email='john@example.org';
- Output on success {BLF-CRYPT}$2y$05$.WedBCNZiwxY1CG3aleIleu6lYjup2CIg0BP4M4YCZsO204Czz07W
- iterate_query: SELECT email AS user FROM virtual_users;
- Output: john@example.org
Testing with openssl
openssl s_client -servername mail.kptree.net -connect mail.kptree.net:pop3s
Testing with doveadmin
doveadm auth test
doveadm auth test john@example.org
, you will be prompted for password. A successful response looks like:
passdb: john@example.org auth succeeded extra fields: user=john@example.org
doveadm user
doveadm user john@example.org
will give output:
field value uid 5000 gid 5000 home /var/vmail/example.org/john mail maildir:~/Maildir quota_rule *:bytes=0
whereas doveadm user *example.org
will give a list of users:
john@example.org
dovecot start / stop
systemd
The debian 10 systemctl dovecot.service:
/lib/systemd/system/dovecot.service
/usr/sbin/dovecot
to start in background- [-F] to start in foreground
- [-c <config file>]
- [reload] forces Dovecot to reload configuration
- [stop] shutsdown Dovecot and all child processes
- [-a] dump configuration settings and exit (it is a long list!)
- [–help]
- [–version]
- [–build-options] show build options and exit
dovecot testing with mutt
Workaround suggests the following command to be used to test: mutt -f imaps://john@example.org@webmail.example.org
The webmail.example.org simple made no sense to me and did not function with error Could not find the host “webmail.example.org”
. As I am creating this in Docker and separately taking the certificates from Traefik, this mailserver simple is not linked in a anyway with a webserver! The webservers for the database access and webmail are totally separate containers. The “simple” solution was to use “localhost” from within the mailserver docker container, e.g. mutt -f imaps://john@example.org@localhost
.
dovecot ssl_dh
I was getting the following error coming up occasionally in my Dovecot log file, “May 25 12:16:05 imap-login: Error: Diffie-Hellman key exchange requested, but no DH parameters provided. Set ssl_dh=</path/to/dh.pem”. To help resolve this error I set up the ssl_dh parameter in 10-ssl.conf, see Dovecot SSL configuration for instructions. The creation of the dh.pem was taking so long on the server that I stopped and created on the desktop, it was much faster. I then simply text copied to the server.
dovecot logging
Dovecot References
- Doc Dovecot:
- Other:
Certificates SSL/TSL
Early on, before 2015 there were not many free SSL certificate providers. I used StartSSL for a free certificate. They would purchased by a company that managed to get their certificate deregister…… So StartSSL basically became non-usable circa 2017. Fourtunately a better solution came about a year or 2 earlier called LetsEncrypt. This could be used with certbot to get free certificates and eventually free wildcard certificates. Then came Traefik which handled certificates.
apache2
Alpine apk apache2 distribution seems to follow the Red Hat setup style. The daemon is httpd instead of apache2. So I need to learn a new setup. Keep features:
- http is the main program,
/usr/sbin/http
httpd -S
list the current definedhttpd -M
list the current defined moduleshttpd -k restart
to restart, also stop to kill, graceful to gracefully stop
- main configuration files located at
/etc/apache2
, including httpd.conf
apache2.4 remote php-fpm proxy configuration
There are a number of ways to configure apache 2.4 to access remote server, see Apache module mod_proxy_fcgi for details. I used the following commands.
DocumentRoot “/var/www/roundcube”
this is not really necessary, however it removes a warning message.ProxyPassMatch "\.php$" "fcgi://roundcubemail:9000/var/www/html" enablereuse=on
basically redirects all *.php requests to the fcgi server.- The first part of the match,
“\.php$”
basically indicates that all *.php call should be directed to the proxy - The second part
"fcgi://roundcubemail:9000/var/www/html" enablereuse=on
is the proxy call (fcgi:) to IP/TCProundcubemail:9000
. The DNS resolves roundcubemail to the local IP address at port 9000. The /var/www/html provides the access path on the remote server.
apache2.4 local php-fpm configuration
nginx and php-fpm
I though I should give nginx a try as I was having linted success with Apache and remote php-fpm.
The Apline package locations as of php version 8.2 are as follows. This may vary with version and also definitely varies with different distributions and their package managers.
- Main php-fpm configuration file is located at
/etc/php82/php-fpm.d/www.conf
- Unfortunately the php version number changes with each setup, so for php version 7.4 the directory would be
/etc/php74/php-fpm.d/www.conf
- Main nginx configuration file is located at
/etc/nginx/http.d/default.conf
Places to change php version number:
- In the Docker file us the variable
ARG PHPVERION=82
- All the /php82/ paths in the pre_start_script.sh,
.config_php/scripts/pre_start_script.sh
- The php-fpm82 reference in
.config_php/s6-rc.d/php-fpm/run
.config_php/etc/php/php-fpm.conf
change the following /php82/ path references:error_log = log/php82/error.log
include=/etc/php82/php-fpm.d/*.conf
Reference
-
- Stackoverflow
php and php-fpm
I decided to setup php-fpm [fpm = FastCGI Process Manager, and CGI = Common Gateway Interface, reputedly more performant than the builtin Apache php module. Amazing an acronym in acronym, some people are so smart they are dumb!]. I basically followed Alpine Linux instructions Apache with php-fpm
php-fpm acts like a php server and can be setup to allow remote connections from clients, usually web pages. The server is normally setup to listen on port 9000. Additional servers can be setup using other ports. This allows servers per app and different server php configuration, e.g. amount of memory and number of process, etc. This is performed by defining additional php-fpm server configuration pools that are differentiated by ip address and port, or socket file. If the client and servers are on the same machine they can communicate via local host and port or via socket file. If remotely hosted they communicate via ip address and port number. The pool definition only allows referencing via discrete ip address and port numbers, where as the web browsers can use name resolution of ip addresses adding flexibility.
Alpine Docker php-fpm
An annoying problem is the php-fpm version is carried on through the file system. The Alpine Docker stable version at writing is 8.1 (called 81). So the following 3 locations need to be considered when updating. This also means that the latest version can not simply be used.
- Dockerfile
ARG PHP_VERSION=82
- Main configuration script
pre_start_script.sh
,PHP_VERSION=82
- s6-rc.d php-fpm longrun start script at s6-rc.d/php-fpm/run, the command
/usr/sbin/php-fpm82 -F
needs to be adjusted manually with version. - Need to create directory in log,
sudo mkdir .config/log/php82
As php-fpm automatically runs in daemon mode, when using s6-rc init as a longrun it needs to be run in foreground mode, /usr/sbin/php-fpm82 -F
, as per the -F option. In daemon mode, s6-rc thinks php-fpm has failed and attempts to restart. As the original program is running, the subsequent repeated attempts to run, give the noted repeated error message. (I believe there is a method in s6-rc to stop after a defined number of failed attempts. I have not looked into this yet.)
- To list installed php modules
php -m
- A comprehensive php information list is provided with
php -i
php-fpm pool
- To check php-fpm defined pools, where xx is the version,
php-fpm82 -tt
- To list php-fpm information,
php-fpm81 -i
, note this is a text version of the the php → phpinfo(); php-fpm82 -h
to list all options- Managing PHP-FPM Learning how php-fpm works will make optimizing your server a breeze! See how to secure and optimize php-fpm here.
- Apache and PHP-FPM Learn to hook Apache up to PHP-FPM using Apache's proxy modules.
references
Roundcube WebMail
I decided to use the Roundcube Docker official image and followed the instructions to setup. As usual I decided to go with the Alpine Linux image option.
My final Docker compose file, docker-compose.yml
See:
- Docker compose: depends_on Depends upon defines start-up and shutdown dependencies on containers in a stack.
- Docker compose: links Links is not specifically required in compose version 3. services connected to a shared network can communicate.
docker compose
Some links:
- dockerhub
Traefik Routing
Looks like Traefik can not handle routing of STARTTLS. At least as of 2023-12-02.
My LAN DNS points to the one common IP address for the mail server. DNS does not differentiate the services via port numbers. As noted I can not use Traefik to perform this routing if the STARTTLS protocol is used. I could possibly use my router, but this is getting too complex.
To allow operation of a Docker Web browser based mail client with my existing VM mail server I used a slightly different URL to help with routing, e.g. webmail.kptree.net versus mail.kptree.net for mail server. The webmail.kptree.net successfully used Traefik router and successfully operated with the mailserver on mail.kptree.net.
References
- Alpine Roundcube seems to be based upon Lighttpd web server and postgres database with manual download of Roundcube.
dmarc
rspamd
redis
- Load the Alpine package
redis
- To start on command line
redis-server /etc/redis.conf &
- The redis configuration file
/etc/redis.conf
is installed with the redis package. - The default conf log file is
/var/log/redis/redis.log
. Usemkdir /var/log/redis
to make directory if required.
- To stop on command line
redis-cli shutdown
- Redis complains if 'vm.overcommit_memory' is not equal to 1.
- This is not set in the container (Docker does have sysctl directive, but not all kernal parameters are support, including this one.)
- This can be set in the host
sudo sysctl -w vm.overcommit_memory=1
Some reference links:
- Redis
nftables
rspamd requires netfilter chains to functions. So a nftables needs to be available and a basic input chain setup to function. See netfilter use within containers that describe why care must be taken no to interfere with existing netfilter nat chains required for container DNS function.
Mailserver testing from CLI
telnet mail.kptree.net 25
Tests the main SMPT mail server connectivity. Port 25 is also designated smtp.telnet mail.kptree.net 587
Tests the mail client SMPT server connectivity. Port 25 is also designated submission.telnet mail.kptree.net imap
Tests the mail client imap server connectivity. The designation imap is port 143.
The mailserver exit control character is '^]' or control key ]. The SMTP and mailserver exit control character is '^]' or control key ].
Errors
Temporary lookup failure. Please check the message recipient "admin@kptree.net" and try again.
https://serverfault.com/questions/506347/postfix-temporary-lookup-failure https://serverfault.com/questions/745545/postfix-rcpt-to-temporary-lookup-failure
References
- Workaround.org ISPmail guide for Debian 11 “Bullseye”
- Gentoo Complete Virtual Mail Server
- Export Traefik Certificates using bash script with
jq
program - Docker documentation specific
- Alpine
- Repositories It is not recommended to mix repositories.
- Dovecot
- Misc