Centos7 Mailserver

Virtual Mail Hosting on Centos7
Using
Postfix MariaDB Dovecot PostfixAdmin Amavisd-new Spamassassin and Clamav

Virtual Mail hosting provides the option of offering mail services to multiple domains on one server.

You will get the following features:

Postfix: the workhorse behind the mail receiving and sending
smtp authentication
secure smtp using TLS
Dovecot: imap and pop3 mailbox service
secure imap and pop3
server side filtering of flagged spam to a spam folder
mysql: handle all the virtual domains and users
PostfixAdmin: GUI for domain administration
roundcube: web mail access
spam/virus filtering using amavisd-new, spamassassin and clamav

This guide was developed from lessons I learned from Campworld Centos6 Virtual Mail Hosting. Plus lots of discussions and near flame wars on lists for many of the packages used here.

A copy of textareas was recently added. The default behavior is to only select the contents of the area on click and the copy to clipboard is a manual step. This is for saftey measures in protecting the content of the clipboard. Below are buttons to allow changing this behavior to copy the area to the clipboard on click.

Further, this guide strives to only modify package config files, rather than replacing them. This is a nod to those package authors on knowing what works best in their packages and easier adoption of new features.

You have a choice of SHA256 or SHA512 for password hashing rather than the default of old MD5. ARGON2 is the, new, recommended password hash algorithm, but not supported until Dovecot 2.3.

Enjoy!

NOTE: The services set up here should be run on a system with at least 1GB of memory with 2GB really being the lower limit. Additionally, though it will run on a duo-core ARMv7 system, a quad core would be better with AMAVIS restricted to 2 core. AMAVIS and CLAMAV can really tie up the system.

FURTHER NOTE: SELinux policies are enforced! In some cases this took working with the SELinux experts to develop polices (e.g. Dovecot to Mysql). No laid back additude of just running in SELinux permissive mode.

Building the Base Server
Installing the Mail packages
Configuring the Mail packages

Setting up MariaDB
Setting up Apache
Configuring Postfix
Configuring Dovecot
Configuring Amavis and Clamav
Configuring Postfixadmin
Configuring Roundcubemail

Testing the Configuration

Building the Base Server

Follow the instructions at: Centos7 for armv7 SOC

to build your base Centos7 armv7 server. Be sure to add the EPEL repo as many of the mailserver packages are there.

Installing the Mail packages

This guide needs the following packages installed:

There is no rpm package for postfixadmin. Get the most recent version at:

http://sourceforge.net/projects/postfixadmin/

Let's assume that the current version you downloaded is: 3.2. Place it in /usr/share.

Then:

Configuring the Mail packages

Throughout this guide, there are values unique to an installation that have to be provided. For the most part, these can be handled by first setting some environment variables that will be used in cat and sed commands. Or you can manually alter the variables. Special characters (\, $, and / tested) MUST be proceeded by a \. Spaces should work with quotes around value entered (but not really tested).

To set date_timezone value. See

http://php.net/date.timezone

for valid timezones (use the same timezone name you used for timedatectl). Set the variables by altering these commands.

Long passphrases may be more secure for the passwords, and not cause problems with the commands, than the use of special characters or spaces.

Three TLS certificates are created in this guide. All should have the following values, but any MAY be left blank. If any include a space, inclose that value in quotes. Special characters can be included, preceeded by \.

Now there is a lot to configure from all these packages and perhaps you are testing from a temporary IP address that is not in DNS. For this you need to add to your /etc/hosts file:

Next we have a lot of firewall rules to add:

Port 587 is used by client smtp to send mail to your mailserver. Port 143 is used by IMAP. Port 110 is for POP3. Port 4190 is used by manageseive. Amavis uses ports 10024 & 10025 but only to localhost so no firewall rule is needed there.

Now edit /etc/php.ini

Now create the mail store directory. Put it in the /home directory to make backups and other item easy.

Setting up MariaDB

Next start MariaDB and secure it. You can manually run mysql_secure_installation, or use the following to auto answer the prompts.

Now setup the mysql database for postfixadmin. The following creates the database and user. The setup URL will create the rest.

Next is the Roundcube database.

Then the tables.

Setting up Apache

This guide uses virtual hosting for the webmail service (Roundcubemail). Virtual hosting requires a DNS entry for webmail.your domain as well as your host. Once virtual hosting is configured, the first virtual host is the default host. Additionally, once a virtual host is set to use TLS, this also becomes the default behavior.

This conf file will load first and force a polite behavior.

The default server access can be restricted with:

Next is postfixadmin's Apache conf file.

Postfixadmin is a Security Risk; Postfixadmin access can be restricted to your IP addresses. Finer control can be added into a /usr/share/postfixadmin/.htaccess file.

Postfixadmin access is via 'http://your_host_tld/mailadmin'. You don't want the whole world accessing this link.

Roundcubemail httpd configuration is next. This guide uses virtual hosting. The conf can be edited to use your_host_tld/webmail.

Further, this guide forces users to https. This is enhanced over the default roundcubemail.conf. Also it secures the cookie used by Roundcubemail. This is an important security deficiency in the default configuration.

cp -b /etc/httpd/conf.d/roundcubemail.conf /etc/httpd/conf.d/roundcubemail.conf.save
bind 'set disable-completion on'
cat <<EOF>/etc/httpd/conf.d/roundcubemail.conf || exit 1
<VirtualHost *:80>

#	Alias /roundcubemail /usr/share/roundcubemail
#	Alias /webmail /usr/share/roundcubemail

ServerName webmail.$your_domain_tld
	ServerAlias webmail

Redirect permanent / https://webmail.$your_domain_tld/
	ExpiresDefault "access plus 1 years"
	php_admin_flag session.cookie_secure "1"

</VirtualHost>

# Round Cube Webmail is a browser-based multilingual IMAP client
#

#	Alias /roundcubemail /usr/share/roundcubemail
#	Alias /webmail /usr/share/roundcubemail

ServerName webmail.$your_domain_tld
	ServerAlias webmail

SSLEngine On
	SSLCertificateFile /etc/pki/tls/certs/webmail.$your_domain_tld.crt
	SSLCertificateKeyFile /etc/pki/tls/private/webmail.$your_domain_tld.key

DocumentRoot /usr/share/roundcubemail

<Directory /usr/share/roundcubemail/>
	Require ip 192.168.0.0/16
# You can enlarge permissions once configured
#	Require all granted
	php_admin_flag session.cookie_secure "1"
</Directory>

</VirtualHost>

# Define who can access the installer
# keep this secured once configured

Alias /roundcubemail /usr/share/roundcubemail

<Directory /usr/share/roundcubemail/installer/>
# You may want to restrict the installer to a single IP address
	Require ip 192.168.0.0/16
</Directory>

# Those directories should not be viewed by Web clients.
<Directory /usr/share/roundcubemail/bin/>
	Require all denied
</Directory>
<Directory /usr/share/roundcubemail/plugins/enigma/home/>
	Require all denied
</Directory>
EOF
bind 'set disable-completion off'

Last step for setting up Apache is creating the SSL certificates. Three certificates are needed. One for webmail.$your_domain_tld, another for $your_host_tld, and the third for localhost. Follow how you setup the roundcubemail.conf and how your users will access your server. The following commands will create the RSA 2048/SHA256 certificates with a 10 years life.

These are self-signed certificates. You can purchase your certificates from a recognized CA. You can find instructions on how to create your own CA and issue these certificates from it. Future work will add a section on using Let's Encrypt certificates.

restore_mask=$(umask -p)
umask 077
cd /etc/pki/tls
commonName=$your_host_tld
openssl req -new -outform PEM -out certs/$commonName.crt -newkey rsa:2048 -nodes -keyout private/$commonName.key -keyform PEM -days 3650 -x509 -extensions v3_req -subj "/countryName=$countryName/stateOrProvinceName=$stateOrProvinceName/localityName=$localityName/organizationName=$organizationName/organizationalUnitName=$organizationalUnitName/commonName=$commonName/emailAddress=$emailAddress"
chmod 640 private/$commonName.key
openssl req -new -outform PEM -out certs/localhost.crt -newkey rsa:2048 -nodes -keyout private/localhost.key -keyform PEM -days 3650 -x509 -extensions v3_req -subj "/countryName=$countryName/stateOrProvinceName=$stateOrProvinceName/localityName=$localityName/organizationName=$organizationName/organizationalUnitName=$organizationalUnitName/commonName=$commonName/emailAddress=$emailAddress"
chmod 640 private/localhost.key
commonName=webmail.$your_domain_tld
openssl req -new -outform PEM -out certs/$commonName.crt -newkey rsa:2048 -nodes -keyout private/$commonName.key -keyform PEM -days 3650 -x509 -extensions v3_req -subj "/countryName=$countryName/stateOrProvinceName=$stateOrProvinceName/localityName=$localityName/organizationName=$organizationName/organizationalUnitName=$organizationalUnitName/commonName=$commonName/emailAddress=$emailAddress"
chmod 640 private/$commonName.key
$restore_mask

You can review the certificate content with:

If you get any of the certificates 'wrong' httpd will not start, and trouble-shooting can be a challenge. Check out /etc/httpd/logs/ssl_error_log for messages hinting at what is wrong with your certificates.

It is now time to enable and start Apache.

Configuring Postfix

Now on to configure the actual packages starting with Postfix.

Postfix is a real task to configure. It will be easier in versions of Postfix beyond 2.10 that is supplied in Centos 7. The following modifies the existing config files, rather than replacing them.

This is a 'best effort' from reviewing a number of sources.

The place to start is with main.cf. Note that message_size_limit limits a message to ~20Meg. Change this as needed.

cp /etc/postfix/main.cf /etc/postfix/main.cf.save
# postfix config file

# uncomment for debugging if needed
#postconf -e 'soft_bounce=yes'

# postfix main
postconf -e 'delay_warning_time = 4'

# network settings
postconf -e 'inet_interfaces = all'
postconf -e "mydomain = $your_domain_tld"
postconf -e "myhostname = $your_host_tld"
postconf -e 'mynetworks = $config_directory/mynetworks'
postconf -e 'relay_domains = proxy:mysql:/etc/postfix/mysql-relay_domains_maps.cf'

# mail delivery
postconf -e 'recipient_delimiter = +'
postconf -e 'content_filter = amavisfeed:[127.0.0.1]:10024'

# mappings
postconf -e 'alias_maps = hash:/etc/aliases'
postconf -e 'transport_maps = hash:/etc/postfix/transport'

# virtual setup
postconf -e 'virtual_alias_maps = proxy:mysql:/etc/postfix/mysql-virtual_alias_maps.cf, regexp:/etc/postfix/virtual_regexp'
postconf -e 'virtual_mailbox_base = /home/vmail'
postconf -e 'virtual_mailbox_domains = proxy:mysql:/etc/postfix/mysql-virtual_domains_maps.cf'
postconf -e 'virtual_mailbox_maps = proxy:mysql:/etc/postfix/mysql-virtual_mailbox_maps.cf'
postconf -e 'virtual_minimum_uid = 101'
postconf -e 'virtual_uid_maps = static:101'
postconf -e 'virtual_gid_maps = static:12'
postconf -e 'virtual_transport = dovecot'
postconf -e 'dovecot_destination_recipient_limit = 1'

# authentication
postconf -e 'smtpd_sasl_auth_enable = yes'
# postconf -e 'smtpd_sasl_security_options = noanonymous'
postconf -e 'smtpd_sasl_local_domain = $mydomain'
postconf -e 'broken_sasl_auth_clients = yes'
postconf -e 'smtpd_sasl_type = dovecot'
postconf -e 'smtpd_sasl_path = private/auth'

# tls config
postconf -e 'smtp_use_tls = yes'
postconf -e 'smtp_tls_exclude_ciphers = RC4, aNULL'
postconf -e 'smtp_tls_loglevel = 1'
postconf -e 'smtp_tls_note_starttls_offer = yes'
postconf -e 'smtp_tls_protocols = !SSLv2, !SSLv3'
postconf -e 'smtp_tls_security_level = may'
postconf -e 'smtp_tls_session_cache_database = btree:$data_directory/smtp_tls_session_cache'
postconf -e 'smtpd_tls_cert_file = /etc/pki/tls/certs/$myhostname.crt'
postconf -e 'smtpd_tls_exclude_ciphers = RC4, aNULL'
postconf -e 'smtpd_tls_key_file = /etc/pki/tls/private/$myhostname.key'
postconf -e 'smtpd_tls_loglevel = 1'
postconf -e 'smtpd_tls_mandatory_exclude_ciphers = aNULL, eNULL, EXPORT, DES, RC4, MD5, PSK, aECDH, EDH-DSS-DES-CBC3-SHA, EDH-RSA-DES-CDC3-SHA, KRB5-DE5, CBC3-SHA'
postconf -e 'smtpd_tls_mandatory_protocols = !SSLv2, !SSLv3'
postconf -e 'smtpd_tls_protocols = !SSLv2, !SSLv3'
postconf -e 'smtpd_tls_received_header = yes'
postconf -e 'smtpd_tls_security_level = may'
postconf -e 'smtpd_tls_session_cache_database = btree:/var/lib/postfix/smtpd_scache'
postconf -e 'smtpd_use_tls = yes'

# rules restrictions
postconf -e 'smtpd_recipient_restrictions = permit_sasl_authenticated, permit_mynetworks, reject_unauth_destination, reject_non_fqdn_sender, reject_non_fqdn_recipient, reject_unknown_recipient_domain'
postconf -e 'smtpd_sender_login_maps = mysql:/etc/postfix/mysql-virtual_alias_maps.cf'

# others
postconf -e 'smtpd_helo_required = yes'
postconf -e 'disable_vrfy_command = yes'
postconf -e 'message_size_limit = 20480000'
postconf -e 'smtpd_data_restrictions = reject_unauth_pipelining'
postconf -e 'smtpd_banner = $myhostname ESMTP'

master.cf is next. I have worked out how to just append needed changes to the end.

cp /etc/postfix/master.cf /etc/postfix/master.cf.save

bind 'set disable-completion on'
cat <<\EOF>>/etc/postfix/master.cf || exit 1
# ==========================================================================
# service type  private unpriv  chroot  wakeup  maxproc command + args
#               (yes)   (yes)   (yes)   (never) (100)
# ==========================================================================
smtpd     pass  -       -       n       -       -       smtpd
submission inet n       -       n       -       -       smtpd
	-o smtpd_recipient_restrictions=
	check_policy_service inet:127.0.0.1:12340
relay     unix  -       -       n       -       -       smtp
	-o fallback_relay=
maildrop  unix  -       n       n       -       -       pipe
  flags=DRhu user=vmail argv=/usr/local/bin/maildrop -d ${recipient}
uucp      unix  -       n       n       -       -       pipe
  flags=Fqhu user=uucp argv=uux -r -n -z -a$sender - $nexthop!rmail ($recipient)
ifmail    unix  -       n       n       -       -       pipe
  flags=F user=ftn argv=/usr/lib/ifmail/ifmail -r $nexthop ($recipient)
bsmtp     unix  -       n       n       -       -       pipe
  flags=Fq. user=bsmtp argv=/usr/local/sbin/bsmtp -f $sender $nexthop $recipient
#
# spam/virus section
#
amavisfeed unix	-	-	y	-	2	lmtp
	-o lmtp_data_done_timeout=1200
	-o lmtp_send_xforward_command=yes
	-o disable_dns_lookups=yes
	-o max_use=20
127.0.0.1:10025 inet n	-	n	-	-	smtpd
	-o content_filter=
	-o smtpd_delay_reject=no
	-o smtpd_client_restrictions=permit_mynetworks,reject
	-o smtpd_helo_restrictions=
	-o smtpd_sender_restrictions=
	-o smtpd_recipient_restrictions=permit_mynetworks,reject
	-o smtpd_data_restrictions=reject_unauth_pipelining
	-o smtpd_end_of_data_restrictions=
	-o smtpd_restriction_classes=
	-o mynetworks=127.0.0.0/8
	-o smtpd_error_sleep_time=0
	-o smtpd_soft_error_limit=1001
	-o smtpd_hard_error_limit=1000
	-o smtpd_client_connection_count_limit=0
	-o smtpd_client_connection_rate_limit=0
	-o receive_override_options=no_header_body_checks,no_unknown_recipient_checks,no_milters
	-o local_header_rewrite_clients=
	-o smtpd_milters=
	-o local_recipient_maps=
	-o relay_recipient_maps=
#
# Dovecot LDA
dovecot	unix	-	n	n	-	-	pipe
  flags=DRhu user=vmail:mail argv=/usr/libexec/dovecot/deliver -d ${recipient}
#
# Vacation mail
vacation unix	-	n	n	-	-	pipe
  flags=Rq user=vacation argv=/var/spool/vacation/vacation.pl -f ${sender} -- ${recipient}
EOF
bind 'set disable-completion off'

And if you have to support Outlook TLS connections, then

Next a number of files in /etc/postfix

mynetworks
mysql-virtual_alias_maps.cf
mysql-virtual_domains_maps.cf
mysql-relay_domains_maps.cf
mysql-virtual_mailbox_maps.cf
virtual_regexp

cat <<EOF>/etc/postfix/mynetworks || exit 1
# This specifies the list of subnets that Postfix considers as
# "trusted" SMTP clients that have more privileges than "strangers".
#
# In particular, "trusted" SMTP clients are allowed to relay mail
# through Postfix.
#
# Be sure to add your public ip address block if needed.
#
192.168.0.0/16
10.0.0.0/8
127.0.0.0/8
EOF

cat <<EOF>/etc/postfix/mysql-virtual_alias_maps.cf || exit 1
hosts = localhost
user = postfix
password = $Postfix_Database_Password
dbname = postfix
query = SELECT goto FROM alias WHERE address='%s' AND active = '1'
EOF

cat <<EOF>/etc/postfix/mysql-virtual_domains_maps.cf || exit 1
hosts = localhost
user = postfix
password = $Postfix_Database_Password
dbname = postfix
query = SELECT domain FROM domain WHERE domain='%s' AND backupmx = '0' AND active = '1'
EOF

cat <<EOF>/etc/postfix/mysql-relay_domains_maps.cf || exit 1
hosts = localhost
user = postfix
password = $Postfix_Database_Password
dbname = postfix
query = SELECT domain FROM domain WHERE domain='%s' and backupmx = '1'
EOF

cat <<EOF>/etc/postfix/mysql-virtual_mailbox_maps.cf || exit 1
hosts = localhost
user = postfix
password = $Postfix_Database_Password
dbname = postfix
query = SELECT maildir FROM mailbox WHERE username='%s' AND active = '1'
EOF

touch /etc/postfix/virtual_regexp

Edit /etc/postfix/mynetworks as needed,

The last step for postfix is the Vacation Email Functionality

And finally create /etc/postfixadmin/vacation.conf

Finally restart postfix

Configuring Dovecot

Dovecot is next. There are a number of Dovecot conf files to edit. Instead, this guide uses the local.conf file which is loaded after the default conf files. By using the default files and local.conf, these modifications should work in future versions of Dovecot. The files altered by the local.conf are:

dovecot.conf
10-auth.conf
auth-sql.conf.ext
10-mail.conf
10-master.conf
10-ssl.conf
15-lda.conf
20-imap.conf
20-lmtp.conf
20-managesieve.conf
20-pop3.conf
90-acl.conf
90-quota.conf
90-sieve.conf

bind 'set disable-completion on'
cat <<EOF>/etc/dovecot/local.conf || exit 1
#	Developed on Dovecot 2.2.36

#	dovecot.conf
protocols = imap pop3 lmtp sieve
dict {
	sqlquota = mysql:/etc/dovecot/dovecot-dict-sql.conf.ext
}

service quota-status {
	executable = quota-status -p postfix
	inet_listener {
		port = 12340
		# You can choose any port you want
	}
	client_limit = 1
}

#	10-auth.conf
!include conf.d/auth-sql.conf.ext

#	auth-sql.conf.ext
userdb {
	driver = prefetch
}

#	10-mail.conf
mail_location = maildir:/home/vmail/%d/%n
first_valid_uid = 101
first_valid_gid = 12
# Space separated list of plugins to load for all services. Plugins specific to
# IMAP, LDA, etc. are added to this list in their own .conf files.
mail_plugins = $mail_plugins quota
mailbox_list_index = yes
# Avoid spending excessive time waiting for the quota calculation to finish when
# mails' vsizes aren't already cached. If this many mails are opened, finish the
# quota calculation on background in indexer-worker process. Mail deliveries will
# be assumed to succeed, and explicit quota lookups will return internal error.
mail_vsize_bg_after_count = 100

#	10-master.conf
service auth {
	unix_listener auth-userdb {
		mode = 0666
		user = vmail
		group = mail
	}
	unix_listener /var/spool/postfix/private/auth {
		mode = 0666
		user = postfix
		group = postfix
	}
}
service dict {
	unix_listener dict {
		mode = 0666
		user = vmail
		group = mail
	}
}

#	10-ssl.conf
ssl_cert = </etc/pki/tls/certs/$your_host_tld.crt
ssl_key = </etc/pki/tls/private/$your_host_tld.key

#	15-lda.conf
postmaster_address = postmaster@$your_domain_tld
protocol lda {
	mail_plugins = quota sieve
}
lda_mailbox_autocreate = yes
lda_mailbox_autosubscribe = yes

#	20-imap.conf
imap_client_workarounds = delay-newmail
protocol imap {
  # Space separated list of plugins to load (default is global mail_plugins).
  mail_plugins = $mail_plugins imap_quota trash
}

#	20-lmtp.conf
lmtp_save_to_detail_mailbox = yes
protocol lmtp {
	mail_plugins = sieve
}

#	20-managesieve.conf
service managesieve-login {
	inet_listener sieve {
		port = 4190
	}
	service_count = 1
	process_min_avail = 0
	vsz_limit = 64M
}

#	20-pop3.conf
pop3_client_workarounds = outlook-no-nuls oe-ns-eoh
protocol pop3 {
	mail_plugins = quota
}

#	90-acl.conf
plugin {
	acl = vfile:/etc/dovecot/global-acls:cache_secs=300
}

#	90-quota.conf
plugin {
        quota = dict:user::proxy::sqlquota
        trash = /etc/dovecot/dovecot-trash.conf.ext
}

plugin {
	quota_grace = 10%%
	# 10% is the default
	quota_status_success = DUNNO
	quota_status_nouser = DUNNO
	quota_status_overquota = "552 5.2.2 Mailbox is full"
}

#	90-sieve.conf
plugin {
	sieve_before = /home/sieve/globalfilter.sieve
}
EOF
bind 'set disable-completion off'

Next the following files are added into /etc/dovecot

dovecot-trash.conf.ext
dovecot-sql.conf.ext
dovecot-dict-sql.conf.ext

Note that the user_query limits an imap mailbox to 30,000 messages. Change this as needed.

mv /etc/dovecot/dovecot-trash.conf.ext /etc/dovecot/dovecot-trash.conf.ext.save
mv /etc/dovecot/dovecot-sql.conf.ext /etc/dovecot/dovecot-sql.conf.ext.save
mv /etc/dovecot/dovecot-dict-sql.conf.ext /etc/dovecot/dovecot-dict-sql.conf.ext.save

bind 'set disable-completion on'
cat <<EOF>/etc/dovecot/dovecot-trash.conf.ext || exit 1
# Spam mailbox is emptied before Trash
1 Spam
# Trash mailbox is emptied before Sent
# 2 Trash
# If both Sent and "Sent Messages" mailboxes exist, the next oldest message
# to be deleted is looked up from both of the mailboxes.
# 3 Sent
# 3 Sent Messages
EOF

cat <<EOF>/etc/dovecot/dovecot-sql.conf.ext || exit 1
driver = mysql
connect = host=/var/lib/mysql/mysql.sock dbname=postfix user=postfix password=$Postfix_Database_Password
default_pass_scheme = $cryptsha-CRYPT
# following should all be on one line.
password_query = SELECT username as user, password, concat('/home/vmail/', maildir) as userdb_home, concat('maildir:/home/vmail/', maildir) as userdb_mail, 101 as userdb_uid, 12 as userdb_gid FROM mailbox WHERE username = '%u' AND active = '1'
# following should all be on one line
user_query = SELECT concat('/home/vmail/', maildir) as home, concat('maildir:/home/vmail/', maildir) as mail, 101 AS uid, 12 AS gid, CONCAT('*:messages=30000:bytes=', quota) as quota_rule FROM mailbox WHERE username = '%u' AND active = '1'
EOF

cat <<EOF>/etc/dovecot/dovecot-dict-sql.conf.ext || exit 1
connect = host=/var/lib/mysql/mysql.sock dbname=postfix user=postfix password=$Postfix_Database_Password
map {
	pattern = priv/quota/storage
	table = quota2
	username_field = username
	value_field = bytes
}
map {
	pattern = priv/quota/messages
	table = quota2
	username_field = username
	value_field = messages
}
EOF
bind 'set disable-completion off'

Now create the sieve filter for SPAM filtering

SELinux needs a policy to allow Dovecot to access the mysql unix socket. As of Feb 5, 2019, this policy has been rolled into Fedora 28 and up, and in time will be included in CentOS.

It is now time to enable and start Dovecot.

Configuring Amavis and Clamav

These two packages work together, along with Spamassassin, to provide anti-spam and anti-virus protection. Their configuration is simple.

With some guidance from https://ismailyenigul.wordpress.com/2015/01/05/install-clamav-on-centos-7/
And more from http://forums.sentora.org/showthread.php?tid=1132
We can get clamav working with the following:

Next edit /etc/amavisd/amavisd.conf.

cp /etc/amavisd/amavisd.conf /etc/amavisd/amavisd.conf.save
cat <<\EOF>>/etc/amavisd/amavisd.conf || exit 1
$mydomain = 'your_domain_tld';
$myhostname = 'your_host_tld';		#  must be a fully-qualified domain name!
$log_level = 1; # set the log level to one
$sa_tag_level_deflt = -99; # I want to see the headers so change to -99
$sa_tag2_level_deflt = 5.0; # start with 5
$sa_kill_level_deflt = 9;
$sa_dsn_cutoff_level = 9;
$sa_quarantine_cutoff_level = 50;
$notify_method = 'smtp:[127.0.0.1]:10025';
$forward_method = 'smtp:[127.0.0.1]:10025';
$final_banned_destiny = D_BOUNCE;
$final_spam_destiny = D_PASS;
@mynetworks = qw( 127.0.0.0/8 [::1] [FE80::]/10 [FEC0::]/10
		10.0.0.0/8 172.16.0.0/12 192.168.0.0/16 your_ipv4_address_block);
@lookup_sql_dsn =
	( ['DBI:mysql:database=postfix;host=localhost;mysql_socket=/var/lib/mysql/mysql.sock', 'postfix', 'postfixsqlpassword'] );
$sql_select_white_black_list = undef;
$sql_select_policy = 'SELECT "Y" as local, 1 as id FROM domain WHERE CONCAT("@",domain) IN (%k)';
1;  # insure a defined return value
EOF
sed -i -e "s/your_domain_tld/$your_domain_tld/w /dev/stdout" /etc/amavisd/amavisd.conf
sed -i -e "s/your_host_tld/$your_host_tld/w /dev/stdout" /etc/amavisd/amavisd.conf
sed -i -e "s/your_ipv4_address_block/$your_ipv4_address_block/w /dev/stdout" /etc/amavisd/amavisd.conf
sed -i -e "s/postfixsqlpassword/$Postfix_Database_Password/w /dev/stdout" /etc/amavisd/amavisd.conf

Finally start it all:

A simple test of clamav is

Test the amavis connection with

You should get

Configuring Postfixadmin

Postfixadmin is the email domain and email account management tool.

Create a base /usr/share/postfixadmin/config.local.php

bind 'set disable-completion on'
cat <<\EOF>/usr/share/postfixadmin/config.local.php || exit 1
<?php
/**
 * Contains configuration options that override the default config file
 */

/*****************************************************************
 * !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
 * You have to set \$CONF['configured'] = true; before the
 * application will run!
 * Doing this implies you have changed this file as required.
 * i.e. configuring database etc; specifying setup.php password etc.
 */
$CONF['configured'] = true;

// In order to setup Postfixadmin, you MUST specify a hashed password here.
// To create the hash, visit /postfixadmin/setup.php in a browser and type a password into the field,
// on submission it will be echoed out to you as a hashed value.
$CONF['setup_password'] = 'changeme';
$CONF['database_password'] = 'postfixsqlpassword';
// Default Aliases
// The default aliases that need to be created for all domains.
$CONF['default_aliases'] = array (
	'abuse' => 'abuse@change-this-to-your.domain.tld',
	'hostmaster' => 'hostmaster@change-this-to-your.domain.tld',
	'postmaster' => 'postmaster@change-this-to-your.domain.tld',
	'webmaster' => 'webmaster@change-this-to-your.domain.tld'
);
$CONF['admin_email'] = 'postfixadmin_email';
$CONF['dovecotpw'] = "/usr/bin/doveadm pw";
$CONF['page_size'] = '20';
$CONF['aliases'] = '50';
$CONF['mailboxes'] = '50';
$CONF['maxquota'] = '100';
$CONF['transport'] = 'YES';
$CONF['vacation'] = 'YES';
$CONF['vacation_domain'] = 'autoreply.change-this-to-your.domain.tld';
$CONF['special_alias_control'] = 'YES';
$CONF['footer_text'] = 'Return to change-this-to-your.domain.tld';
$CONF['footer_link'] = 'http://change-this-to-your.domain.tld';
$CONF['create_mailbox_subdirs']=array('Drafts','Spam','Sent','Trash');
$CONF['create_mailbox_subdirs_host']='localhost';
$CONF['create_mailbox_subdirs_prefix']='';
$CONF['quota'] = 'YES';
$CONF['used_quotas'] = 'YES';
$CONF['new_quota_table'] = 'YES';
// $CONF['create_mailbox_subdirs_hostoptions']=array('notls');
$CONF['create_mailbox_subdirs_hostoptions']=array('novalidate-cert','norsh');
$CONF['encrypt'] = 'dovecot:cryptsha-CRYPT';
$CONF['dovecotpw'] = "/usr/bin/doveadm pw ";

//
// END OF CONFIG FILE
//
?>
EOF
bind 'set disable-completion off'
sed -i -e "s/postfixadmin_email/$admin_email/w /dev/stdout" /usr/share/postfixadmin/config.local.php
sed -i -e "s/postfixsqlpassword/$Postfix_Database_Password/w /dev/stdout" /usr/share/postfixadmin/config.local.php
sed -i -e "s/cryptsha/$cryptsha/w /dev/stdout" /usr/share/postfixadmin/config.local.php
sed -i -e "s/change-this-to-your.domain.tld/$your_domain_tld/gw /dev/stdout" /usr/share/postfixadmin/config.local.php

SELinux seems to be a problem for Postfixadmin (and Roundcubemail which needs the setsebool).

Now go to host/mailadmin/setup.php

Setup should proceed to create/update its database structures.

Next is creating the Setup Password by clicking by entering password and clicking on generate hash. Then edit /usr/share/postfixadmin/config.local.php with the provided hash.

Use this password to add your postfixadmin admin account. Use this account to log into host/mailadmin. Create a mail domain; set up a DNS MX entry for it and create a user. Postfixadmin should set up all the files for the user and send it a welcome message that will be the basis for testing the components.

Configuring Roundcubemail

Roundcubemail configuring is easier now with the installer, but there are a few permission items to take care of first.

Roundcubemail is written in php and a couple php defaults may not be right for Roundcubemail, particularly the file upload size and message size maximums. The following will comment out the defaults and add new maximums. Change them as you need.

Depending on how you setup roundcubemail.conf for httpd

The installer does most of the work. Things to do in the install include:

In the General configuration, select Enchant spellcheck_engine.

In the Database section set your Roundcubemail MySQL password.

In the IMAP section, change the junk_mbox to Spam.

In the SMTP section,
set smtp_server to fqdn
Check "Use the current IMAP username and password for SMTP authentication"

In the Plugins section,
Check managesieve
Check password

Click the UPDATE CONFIG button, start a

cat > /etc/roundcubemail/config.inc.php

copy the content of the text box into the prompt and end with a Cntl-D.

Do not add a closing ?> tag.

Follow the instructions to test Roundcubemail.

If in your system 0 quota means no limit

To allow browser-autocompletion of username and host on login form.

To directly delete messages in Junk instead of moving to Trash.

This quide uses 'Spam' for the 'Junk' folder. To force Roundcubemail to display 'Spam', rather than 'Junk' as default.

Apache is configured to redirect to secure connections. Roundcubemail can check and redirect if the Apache configuration is wrong with:

Now we set up the manage sieve plugin.

For the password plugin:

Restart Apache.

Testing the Configuration

This completes configuring the software. Next are some tests to confirm things are working.

Use Postfixadmin to create a virtual domain and a user or so. Use Roundcubemail to log into a user account and check receipt of the Postfixadmin welcome message.

Roundcubemail use did a basic test of dovecot imap access. For a fuller test, use all of the following connection methods (via fqdn from a remote system).

IMAP log in and some commands are

POP3 log in and some commands are

For more on Dovecot testing see

http://wiki.dovecot.org/TestInstallation

For anti-virus testing, find sample.tar.gz.compl (check the version of amavisd-new) and change to that folder and untar it

Then send the following emails. virus-sample should be dropped, GTUBE should be moved to Spam, and README should end up in INBOX.

Updated 06/19/2019